And I have nothing to add to this:

If they complain about amounts, tell them to complain to me. It's best if sources try to exhaust their source allocations, even if it means giving posts higher amounts than is typical. If you have 150 source merit and you only see 3 merit-worthy posts in a month, then I'd rather you over-give each of them 50 merit than let the merit expire. That way there are more people capable of sending merit, and the "merit economy" is less top-down.

If a DT member tags you for something stupid involving merit (ie. probably anything less than selling merit), then they're not going to be a DT member for much longer.

Aside from that, if people complain about whether things deserve merit at all, then that's something to perhaps think about, but if you conclude that they're wrong, then that's that. You don't need to stress about it or defend yourself constantly. It's conceivable that someday you and I will end up disagreeing too much about this stuff and I'll remove your source status, but it's really not a big deal.

The topsendban list is just a first indication of abuse, and many excellent people are on it. Your place on there acts as a sort of benchmark: eg. chandra12 has a similar score there, but whereas you are an extremely active merit-giver with a diverse selection of posts merited (most of which anyone would agree with), chandra12 only has two large merit sends. His behavior in comparison to yours while having a similar topsendban score is what creates a strong abuse impression.

I appreciate the work of you and other sources who take it seriously!