i would agree with you that it seems like most Rabbis don't interpret the verse the way you do, and mostly interpret it to mean that the miswah only applies to converts or other Jews. But sprinkled here and there in our history, there are Rabbeim who interpret the verse as you (and arguably Sefer HaChinuch) does. i'm sure there are more examples, but it seems to me that that the Orthodox world of today tries to censor these thoughts out by removing these comments from the mainstream books, by discrediting them (usually with arguments they weren't orthodox enough) like as has been done to the Hertz Chumash.
From the Hertz Chumash, written by the former Chief Orthodox Rabbi of the United Kingdom from 1913-1946.
Commentary to Leviticus 19:18
Though the founder of Christianity quotes ‘Thou shalt love thy neighbour as thyself’ as the old
Biblical command of recognized central importance, many Christian theologians maintain that the
Heb. Word for ‘neighbor’ (rea) in this verse refers only to the fellow-Israelite. Its morality therefore
is only tribal. But the translation of the Heb. Word rea by ‘fellow-Israelite’ is incorrect. One
need not be a Hebrew scholar to convince oneself of the fact that rea means neighbour of whatever
race or creed. Thus in Exodus XI, 2 – ‘Let them ask every man of his neighbour, and every
woman of her neighbour, jewels of silver, etc.’ – the Heb. Word for neighbour cannot possibly
mean ‘fellow-Israelite’, but distinctly refers to the Egyptians. As in all the moral precepts of
Scripture, the word neighbour in Lev. XIX, 18, is equivalent to ‘fellow-man’, and it includes in its
range every human being by virture of his humanity.
Additional Leviticus Notes (Page 563 of the Hertz Chumash)
"The Golden Rule In Judaism - The world at large is unaware of the fact that this
comprehensive maxim of morality - the golden rule of human conduct - was first taught by
Judaism...
"In the generation after the destruction of the temple, rabbi Akiba declares ' "Thou shalt love thy
neighbour as thyself" is a fundamental rule in the Torah.' His contemporary, Ben Azzai agrees that
this law of love is such a fundamental rule, provided it is read in conjunction with Gen. V, 1 ('This
is the book of the generations of man. In the day that God created man, in the likeness
of God made He him'); for this latter verse teaches reverence for the divine image in man, and
proclaims the vital truth of the unity of mankind, and the consequent doctrine of the brotherhood
of man. All men are created in the Divine image, says Ben Azzai; and, therefore, all are our fellowmen
and entitled to human love."
Commentary of Leviticus 19:18 by Rabbi Raphael Samson Hirsch
ואהבת לרעך כמוך אני ה'. זה כלל מסכם לכל התנהגותנו החברתית - בדיעות, במלים ובמעשים..
ידוע מאמרו של הלל: "דעלך סני לחברך לא תעביד"..."השנוי עליך א-ל תעשה לחברך": הרי כאן שוויון גמור לכל - כעיקרון מנחה לכל פעולותינו; על - פי זה נדרוש את שלום רענו כשלומנו; נהפוך אנוכיות ואהבה עצמית לאהבת ריע ולשמירת כבודו; נלמד לאהוב ולכבד כל נברא בשוויון גמור עמנו. אכן מושג "חברך" במשמעותו הרחבה כולל כל נברא, ולא רק כל אדם; ובמשמעות רחבה זו הרי כאן באמת תמצית כל התורה. שהרי זו כל כוונת התורה: היא מרחיקה אותנו מכל "סני": מכל המתנגד באיבה לשלומנו ולשלום כל נברא שבחברתנו
"Love your neighbor's well-being as if it were your own; I am God," is
the summarizing final maxim for the whole of our social behavior, in
feelings, word, and deed. Hillel’s interpretation of this as: “That
which is hateful to you don’t do to someone else” imposes complete
equality of all as the guiding principle of all of our deeds, makes
everyone take to heart the weal and woe of everybody else, changes
selfishness…into consideration and love of one’s neighbor. The concept
of “your neighbor” extends the ideas beyond the narrow confines of
your fellow men to the idea of fellow creatures, so that in fact this
sentence does contain the contents of the whole Torah, which indeed is
nothing else, but the teaching of avoiding everything which is
contrary and hateful to the happiness and well-being of ourselves and
to that of the fellow creatures who enjoy existence down here in this
world.
http://www.on1foot.org/text/rabbi-samphson-rafael-hirsch-commentary-leviticus-1918-pentateuch-vol-1-genesis