I respectfully disagree.
If this is the marker for LCC, then carriers like BA are in this group too.

I also fail to understand why it is such a bad thing. If there is a crowd willing to pay for this (and another crowd that doesn't care for seats, as long as they get the cheapest tickets around), then this will benefit many travellers?

Many airlines, including AY, are not profitable businesses. They will work with cutting costs and finding new revenue. OK, so let's say they wouldn't care for getting revenue from seat selection. Then they would need to cut costs even more. I cannot see how that would benefit travellers in a better way.