The Holocaust
Pogroms
Lack of equal rights
Harassment
However, there are countries like the United States where this does not exist, or more precisely exists at lower levels. But in addition to all these reasons there is also the matter of massive assimilation. In the United States it is 60 percent assimilation.

Hello and blessings, Rational (Relatively), indeed, it was toward an answer like yours that I intended my question. It is worth noting that over the course of about 2,500 years, Jewish life in exile was conducted quite well and pleasantly, aside from marginal events (in historical perspective, painful as they may be, perhaps except for the Holocaust). I think the main difficulty in exile is not the physical / emotional suffering in its various aspects of everyday life, but on the contrary: the main suffering in exile was the lack of possibility to fulfill Torah and the commandments as the aspiration of the people.
I know my words sound strange, but certainly the suffering of the children of Israel matched that of other tribes (peoples) in Europe during the period in question, and many times their situation was much better.

What significance is there to the assimilation of someone who does not observe the commandments? At least his children will not be obligated in the commandments. Besides, from a halakhic standpoint it is preferable that he assimilate.

A, I’m not sure that from a religious point of view you are right. It depends whom you ask.
I think that if you ask the school of Rav Kook and the idea of Israel’s unique spiritual quality, it is always preferable that your children remain Jewish even if they gorge themselves on non-kosher carcasses and have relations with prostitutes. For the Jewish spark may return to each of your descendants in the future. And also on a personal level, all Israel have a share in the World to Come (and there are many disputes over whom to exclude from the community of Israel, and whether heretics who are not intentional are included among Israel and have a share in the World to Come or not—but certainly sinners out of appetite do have a share in the World to Come).

And according to the Haredi approach, apparently you are right.

Do have*
Non-kosher carcasses and improperly slaughtered animals*

I disagree. Of course, one can find approaches with esoteric and mystical views, but that is not Judaism. At least not mainstream Judaism.
What is Jewish about someone who does not observe the commandments? According to the Shulchan Arukh and Maimonides, one should throw him into a pit and not pull him out, as explained in Avodah Zarah 26b (and this includes even “one who eats carcasses out of appetite”). A Jew who publicly desecrates the Sabbath is considered an apostate to the entire Torah, and his law is like that of a gentile. There is no meaning to Judaism without observance of the commandments.
At least from a religious point of view. As Rav Saadia Gaon said: “Our nation is a nation only through its Torah.”

I do not know why you think that an apostate out of appetite is okay. More than that, the Rabbi has several times on the site maintained that heretics are preferable to apostates out of appetite, because the latter recognize the Torah and the Creator and transgress it, whereas the heretic is intellectually coerced.
There is, of course, an opinion that a heretic is someone who knows his Creator and rebels against Him, not someone who simply does not believe in Him, and according to this opinion you are apparently right. But what heretics like that do you know?

Also from a personal point of view (a gentile has a better chance of reaching the World to Come, and only 7 commandments are enough for him), also from a metaphysical point of view (according to Kabbalah, sins destroy worlds), and also from a national point of view (“Our nation is a nation only through its Torah,” and the fact is that secular Jews ultimately leave Judaism), it is preferable that the secular person assimilate (and along the way also commit at least one less transgression).