That's exactly why it IS logical though. Playing a Throne Roomed Feast:
"Trash this card"
Okay, into the trash you go.
"Gain a card costing up to $5
Excellent, that's another Copper for the stack! Now I play my Feast again.
"Trash this card"
What card? I can't do this!
"Gain a card costing up to $5"
Okay. Fancy some variety, I'll have an Estate.
The clauses are seperate, so it's fine. Compare to running it with Treasure Maps.
"Trash this card and another Treasure Map from your hand"
Okay, treasure map in hand, and in play into the trash. Ooh, I wonder what's coming next?
"If you do, gain 4 Golds, putting them on top of your deck"
Well, I actually wanted more coppers, but... I guess I can live with this.
Now I play it again.
"Trash this card and another Treasure Map from your hand"
Huh? Well, here's the Map in my hand into the trash, but I can't find the 'this card' that's being referred to. Eh, can't affect much.
"If you do, gain 4 Golds, putting them on top of your deck"
Oh, hey, I guess I couldn't do that last thing. That's good, don't want my deck clogged with Golds.
The good thing about dominion cards is you can interpret them literally and get the correct result 99.8% of the time if you know the underlying rules. The bad thing is that a lot of people (and I don't mean this in an insulting way, just it's kinda how people are) don't get that literal interpretation thing, and make mental shortcuts that don't always work. Throne Room and Treasure Maps are two offenders, and together can be problematic.