Irrelevant case in Chagiga 1:7?

Question

The Mishna in Chagiga 1:7 continues from the previous mishna (1:6) in talking about different explanations for the passuk (Kohelet 1,15):״מעות לא יוכל לתקון וחסרון לא יוכל להימנות״- “a crookedness that cannot be fixed, and something missing that cannot be counted.”

רַבִּי שִׁמְעוֹן בֶּן מְנַסְיָא אוֹמֵר, אֵיזֶהוּ מְעֻוָּת שֶׁאֵינוֹ יָכוֹל לִתְקֹן, זֶה הַבָּא עַל הָעֶרְוָה וְהוֹלִיד מִמֶּנָּה מַמְזֵר. אִם תֹּאמַר בְּגוֹנֵב וְגוֹזֵל, יָכוֹל הוּא לְהַחֲזִירוֹ וִיתַקֵּן. רַבִּי שִׁמְעוֹן בֶּן יוֹחַאי אוֹמֵר, אֵין קוֹרִין מְעֻוָּת אֶלָּא לְמִי שֶׁהָיָה מְתֻקָּן בַּתְּחִלָּה וְנִתְעַוֵּת, וְאֵיזֶה, זֶה תַּלְמִיד חָכָם הַפּוֹרֵשׁ מִן הַתּוֹרָה:

Rabbi Shim’on Ben Menasiah says, what is “a crookedness that cannot be fixed”? One who comes to his relative (that he is prohibited to come to) and births a mamzer son. If you would try to say that it is talking about a thief, he can return the stolen item, and his crookedness is fixed. Rabbi shim’on Bar yochai says, we do not call something crooked, unless it was originally straight. What is this? A Torah scholar who left the Torah.

Why does Rabbi Shim’on Ben Menasia assume we’ll think that the passuk is talking about a thief over anything else, and why at all?

What does a thief have to do with this passuk, or this Mishna?

Answer 1

The pasuk being referred to is from Koheles 1:15 links both parts with a Vav Hachibbur which implies that the reference is two facets of the same action:

מְעֻוָּ֖ת לֹא־יוּכַ֣ל לִתְקֹ֑ן וְחֶסְר֖וֹן לֹא־יוּכַ֥ל לְהִמָּנֽוֹת

חֶסְר֖וֹן means something physically missing (e.g Kings I 17:16- "הַשֶּׁ֖מֶן לֹ֣א חָסֵ֑ר") missing i.e stolen at a first glance so that's why Rav Shimon ben Menasia declared that the plain meaning does not fit because something physically stolen could be given back unlike the Passuk which states "it cannot be accounted for."