Exempt from mitzvah and do it, have you fulfilled it contradiction

Question

In Hilchos Kriyas Shema, the SA (OC 71:1) says

מִי שֶׁמֵּת לוֹ מֵת שֶׁהוּא חַיָּב לְהִתְאַבֵּל עָלָיו, אֲפִלּוּ אֵינוֹ מֻטָּל עָלָיו לְקָבְרוֹ, פָּטוּר מִקְּרִיאַת שְׁמַע וּמִתְּפִלָּה.

Someone whose relative died, one who they must mourn for, even if the body isn't their responsibility to bury, they are exempt from reciting the Shema and praying.

They're exempt from other mitzvos as well (Mishnah Berurah s.k. 4).

‏ (ד) ומתפלה - וכן מכל הברכות אפילו ברכת הנהנין ומכל מצות האמורות בתורה

From prayer - and also all other blessings, even blessings on items of pleasure, and from all mitzvos in the Torah.

The Mishnah Berurah s.k. 3 adds an important detail:

‏ (ג) פטור וכו' - ואם קרא אינו יוצא וצריך לחזור ולקרות אחר הקבורה. [חידושי רע"א]:

And if you recited shema, you haven't fulfilled your mitzvah and you have to recite it again after the burial

We see from here that someone who is exempt from a mitzvah, doing the act isn't considered doing the mitzvah, so they haven't fulfilled the obligation (meaning if they become obligated later they can't rely on what they did earlier).

However, in Hilchos Pesach the SA (OC 475:5) says

אָכַל כַּזַּיִת מַצָּה וְהוּא נִכְפֶּה, בְּעֵת שְׁטוּתוֹ, וְאַחַר כָּךְ נִתְרַפֵּא, חַיָּב לֶאֱכֹל אַחַר שֶׁנִּתְרַפֵּא, לְפִי שֶׁאוֹתָהּ אֲכִילָה הָיְתָה בְּשָׁעָה שֶׁהָיָה פָּטוּר מִכָּל הַמִּצְוֹת.

Someone who was in a state of insanity and ate matzah and later became better, they have to eat matzah again. This is because when they ate the matzah the first time, they were exempt from all mitzvos.

The Shaar HaTziyun s.k. 39 adds a case:

‏לאפוקי שומר אבדה או משמר המת, אף דהוא גם-כן פטור אז מכל המצות [ואפילו יכול לקיים שניהם, אם צריך לטרוח אחר זה]...אם אכל אז מצה יצא ידי חובתו, דהוא איש, אלא שאז לא חייבתו התורה מפני שהוא עוסק במצוה אחרת.

Unlike someone guarding a lost object or a dead body, even though they are also exempt from all mitzvos (even if they could fulfill both, in the case that they have to add exertion to fulfill the second mitzvah)...if they ate matzah at that point, they have fulfilled their obligation. This is because they are a normal person (unlike someone deranged), just the Torah exempted them because they're doing a different mitzvah.

I see a glaring contradiction here. Someone exempt from a mitzvah who does it anyways, did they fulfill it or not? You could argue one is a case of אונן and one עוסק במצוה, but I don't see the distinction. Besides, I believe an onen is exempt because they have the status of one who is עוסק במצוה, (I found the Magen Avraham says this, although Rashi in Berachos says onen is equivalent to a chasan on his wedding night, טרוד במצוה which is related to עוסק במצוה).

Edit: I found another instance where the Mishnah Berurah (70:4 s.k. 18) says someone עוסק במצוה, if they recite Shema, they've fulfilled their obligation. So this seems to be a rule with עוסק במצוה. The only question then is how to differentiate an אונן. Although now I'm wondering if it makes a difference that the person stopped the mitzvah they were עוסק in, and then did the other mitzvah.

Answer 1

R. Asher Weiss asks this question on the Mishnah Berurah in Minchat Asher, Devarim 11:3.

His answer is that Mishnah Berurah must hold (unlike Rashi) that the exemption of onen from mitzvot is not (solely) due to his status as an osek bemitzvah, but because of the principle of kevod hamet (behaving respectfully toward the dead).

A regular osek bemitzvah is technically obligated in the commandment, but has a legitimate reason not to perform it. If he performs it anyway, it counts.

An onen is fundamentally exempt (mufka) from all mitzvot, so his performance of the commandment is meaningless.

Answer 2

The Mishna Berura answers this question by saying that he's not technically Patur when he is an Osek Bamitzvah, but rather, it's just a matter of priorities:

משנה ברורה סימן ע ס"ק יח: " (יח) לא יפסיק - ואם יכול להפסיק לק"ש ואח"כ לחזור ולגמור צרכי צבור בלא טורח יפסיק. כתב הפמ"ג דאע"ג דהעוסק בצרכי רבים פטור מק"ש מ"מ אם פסק וקרא שפיר יצא ידי חובה דלא פטור ממש מק"ש אלא שהוא אז עוסק במצוה אחרת:‏

If follows that when one is an Onen or Shotah, they are actually Patur from Mitzvos, as we see in the Shulchan Aruch you quoted:

אָכַל כַּזַּיִת מַצָּה וְהוּא נִכְפֶּה, בְּעֵת שְׁטוּתוֹ, וְאַחַר כָּךְ נִתְרַפֵּא, חַיָּב לֶאֱכֹל אַחַר שֶׁנִּתְרַפֵּא, לְפִי שֶׁאוֹתָהּ אֲכִילָה הָיְתָה בְּשָׁעָה שֶׁהָיָה פָּטוּר מִכָּל הַמִּצְוֹת.‏

Answer 3

A person needs to be in a certain mental state to be able to Daven or read Krias Shema. The Gemara says that the Chassidim Rishonim would wait 1 hour before davening.

Krias Shema is Kabbalas Ol Malchus Shomayim and needs to be done with proper intent (and needs Kavanah, see Brachos 13a).

However, eating Matzah is not so! The Gemara in Rosh Hashana 28a says that

שלחו ליה לאבוה דשמואל כפאו ואכל מצה יצא כפאו מאן אילימא כפאו שד והתניא עתים חלים עתים שוטה כשהוא חלים הרי הוא כפקח לכל דבריו כשהוא שוטה הרי הוא כשוטה לכל דבריו

It is related that the following ruling was sent from Eretz Yisrael to Shmuel’s father: If one was forcibly compelled to eat matza on Passover, he has fulfilled his obligation. The Gemara clarifies the matter: Who compelled him to eat the matza? If we say that a demon forced him, i.e., that he ate it in a moment of insanity, this is difficult. Isn’t it taught in a baraita: With regard to someone who is at times sane and at times insane, at the times when he is sane, he is considered halakhically competent for all purposes and is obligated in all the mitzvot. And when he is insane, he is considered insane for all purposes, and is therefore exempt from the mitzvot. If so, someone who was compelled by a demon to eat matza is not considered obligated to perform the mitzvot at all.

You can even be forced to eat Matzah and be Yotzei.

Many Acharonim point out this is similar to the Halacha that מתעסק בחלבים ועריות חייב שכן נהנה.

Therefore, we can differentiate between the Mitzvos being talked about.

This is the first way to differentiate. The second way is that Tosfos, multiple times in Brachos say that Onen is Assur to do a Mitzvah, not that they are not Chayav. Therefore we do not relate to their action as a Mitzvah, unlike an Osek Bemitzvah. I think this is the most simple way to differentiate. Tosfos in Brachos 17b explicitly say this.

So if someone is assur to do something, then we don't count it as a Mitzvah.

If they are Patur, then we do.

(and the case of insanity is not relevant as it is not viewed as your action)