Through the bullshit, there were some interesting new reasons I had not though of, so a thank you to the levelheaded for educating me.
To wrap it up: here is my 100% subjective opinion on the 5 shades of grey with regards to alt accounts. Please ignore the random numbers.
This one suprised me the most: those who have alts to boost other players. Needless to say, yall are the real MVPs.
I think a lot of the hardcore completionists who are also active on this forum fall in this category. As much shit I give Krid for his alt, I think this category is perfectly fine.
Edit: I would throw self-boosters into this category as well.
I created an alt when I had just bought a PSVR set, because I was worried I would be too nauseous to finish an added game. Didn't end up using it a lot, because I quit completionism shortly thereafter.
Similarly, this is for those who use an alt to test if a game is for them before comitting, and I think this is were the proper grey starts as to what is "generally" considered fakepletionism.
These are the people who see a game with an awesome story but with "unreasonable" trophies* and don't let their hobby get in the way of enjoying it.
* (difficulty- or timewise, and maybe luckbased)
Similar to 4 but without the factor of "story": relegating games based on difficulty/time-commitment to an alt, to prevent tarnishing their "100% pristine profile".
That's all folks. Enjoy your games and hobbies, and don't care too much what people like me think.