> her an ungrateful jerkass
It was just a joke after Kogasa demanded money, it was a way for Kogasa to get punishment that she deserved for being a traitor.
> The execution of that peaceful newly-turned youkai in FS on the other hand was downright hypocritical,
How is it hypocritical?
> unfair regarding other youkai and well,
How? You know other youkai aren't villager jinyous?
> pretty damn unexpectedly cruel.
No it isn't, it's the rules and also her job, if she DIDN'T kill him Reimu would have done wrong, hell this is probably the first time Reimu has done her job properly, ever.