Deletionism is the only reason Wikipedia remains using. Without deletions, it would have sunk into the world of spam-trap and personal blog platform long ago.
> I still get nuclear physics in "Nuclear Physics" article, amn't I?
Not at the same level of quality, because they also won't be deleting the nonsense crank pseudo-science version of "Nuclear Physics" which would confuse you terribly. Deleting crap is one of the best ways to make the project as a whole useful.