Commits should be reasonably small, logical, and atomic. MRs represent a larger body of work than a commit in many cases. My average number of (intentionally crafted) commits is like 3-5 in an MR. I do not want these commits squashed. If they should be squashed, I would have done so before making the MR.

People should actually just give a damn and craft a quality history for their MRs. It makes reviewing way easier, makes stuff like git blame and git bisect way more useful, makes it possible to actually make targeted revert commits if necessary, makes cherry picking a lot more useful, and so much more.

Merge squashing everything is just a shitty band-aid on poor commit hygiene. You just get a history of huge, inscrutable commits and actively make it harder for people to understand the history of the repo.