I think it depends. An athlete might want to keep the same or less weight for performance or aesthetical reasons.

I meant that the problem many atheists have is consuming enough calories rather than too many. But I guess it depends on the discipline. Triathletes, for example, would burn plenty of more calories training than boxers might.

Back when I was athletic, I definitely had a problem putting weight on rather than taking it off.

This is definitely typo of the week.

Protein powder is full of fake sweeteners

That is true for many brands.

This is not a reason to avoid it, but to be very careful when shopping and to buy only something that is not adulterated with anything, for instance pure whey protein concentrate or isolate (when produced correctly, those are made by just filtering the whey, without adding anything, though even some of the companies that do not add sweeteners still add lecithin as emulsifier and an anti-caking agent, to be able to market the powder as "instant"; however these additives are far more benign and in far smaller quantities than sweeteners and fragrances).

Depends if you're in a weight restricted sport or not