JiffyPopTart
Bree-Yark
And equally true at the same timeCorrect. Orcs + Str, Elves + Dex. Different.
Orc+STR, Orc+INT. Different
Your logic applies to both sides of the discussion of what method makes characters the most "different".
You view a half-orc wizard as not a fundamentally different character than a human wizard (if both have a 17 INT at 1st level) but at the same time see it as reinforcing your campaign bedrock if you limited that same half-orc to a 15 INT while at the same time pointing out nobody NEEDS a 16 because one bonus point isn't a major penalty to a characters gameplay.
Either that small difference is significant (both to your campaign AND a player wanting a smart half-orc) or it isn't significant (in which case it's not contributing to the feel of your world and people should be happy to play a 15INT half-orc).
You can't have it both ways.