The default should be that races have racial ASIs. This retains differences between races (really, closer to species) in D&D: Orcs are stronger than the average person; halflings are more cunning; elves are more dexterous; etc. Just as it is nonsensical to say that cheetahs aren't more dexterous than elephants, it is nonsensical to say that orcs aren't stronger than gnomes.
That said, I'm in favor of optionally allowing any +2/+1. This was a homebrew rule in many of the tabletop games I played in. With bounded accuracy a difference of +1 is significant, and so using point buy can result in a race-class combination that both doesn't fit the idea of your character and is suboptimal (especially because some stats--if your're not playing a class based on that stat--are truly dump stats in 5e). Additionally, optionally allowing any +2/+1 sets your character apart from your race's dominant traits, which is a perfect opportunity for defining your background and roleplaying that uncommonly high off-stat or that uncommonly-low racial stat.
But in order to be different than your race, in order to have that above roleplaying opportunity, there needs to be a default racial mold that your character doesn't match.