That's such a lame excuse... it shows just the lazyness on the dev's side, of course you have problems with this if you only use premade poses, and of course you have problems with this if you don't know how to change/correct a pose.
I'm not saying that there aren't other reasons, like time or ressources (which is a big factor especially for animations), but what you mentioned is nothing more than a simple excuse for beeing lazy.
I agree 100% with you, it differentiates the good devs from the "newer" ones... Not everyone is going to be able to edit a pose again and again till its spotless, most are just thinking "good enough"... so pre-made poses are obviously going to be used more than creating their very own...
However to be fair I prefer they use that excuse (not enough posing talent) when asked, rather than the lameass excuse someone used earlier... power fantasy ? wanting to feel alpha as fuck ? thats horseshit... its as bad as the NTR defenders saying "those poloygons that compose the female model arent really your waifu, and your not the male MC"... that applies to less than 20% of the people !!
To me its annoying to see horse dicks and it be deliberate cause is fulfilling some stupid ass fantasy that some basement dweller has...
Lets take your game for example, Bad Memories, the guy is big but not monstrous... if he had a dick the size of the MC from Summoner's Legacy, and you made it disappear in the autistic baby sister from your game, I'd call BS.. no matter how good you were at rendering, you can see the size of that thing, and the size of your female model... there is no way it doesnt come out her throat if your going by polygon count /size.
Again I think either both excuses are valid, or neither fully is... cause we dont all have penis envy, we dont all feel inadequate, just like how not all devs struggle with posing.