The logic is that if you make your opponents weaker, year after year, you don’t need to hunt around Europe to pay huge transfer fees, which seems to go against the sporting integrity argument they like to use against City, amongst others.
They have, of course, been architects of a system that has given Germany the same league winner for 9 consecutive seasons, for 16 seasons in the last 20, and for 30 seasons since their second title in 1969. Doesn't seem to work like a model for sustained sporting competition, would be my major complaint.
I don't even mind that, it's each to their own. If only they would mind their own business though.