You said it's a contradiction that I say that a) Google exploits developers (in a way) and b) developers [can try to] to exploit Google. I made an over-the-top example to show that these two are not mutually exclusive.

I think by using an irrelevant example you inadvertently demonstrated the exact opposite - that they are.

If two parties "economically exploit each other equivalently", there is no exploitation.

These are not the same people, however. There are the developers which give in to the rules and process their payment via the app store. These are somewhat exploited by having 30% of their profits taken. Then there are those which circumvent the store payments by using external integrations and therefore exploit Google by denying them their fair share[0]. These groups are distinct.

[0] Whereas the "fair share" is not necessarily 30%, but >0%.