Even the most minute treat production is bad because we as a species still struggle with providing the essentials of life to everyone, which makes the production of luxuries bad.

I agree with the premise, but I don't think it applies here. We don't actually struggle with providing the essentials of life to everyone, we simply aren't trying to. There are more empty houses than homeless people, enough food to feed everyone on Earth no problem. But the houses lay empty and the food goes in the trash. Cutting treat production will not solve the problems mentioned because the problem is not that there are too many treats and not enough essentials.

Asceticism is bad because it’s a strictly anti-materialist philosophy that has its roots in theology

The core of asceticism is "you don't need stuff to be content" which is backed up by my own experiences in the real material world. I don't really care what it has its "roots" in.

as communists we want everyone to have the same amount of things

🙄

and that would require everyone participating in leisure which an ascetic would find materialistic.

You're going to go to the ascetic's house and force him to play mario kart at gunpoint?