When your name is on the bill you sponsored, it is you who is given credit for writing it.
If his aide wrote it, he shoulda checked it before putting his name at the bottom of it.
The fact that it's been enacted, and the names redacted, and there's been no firings in his office over it, tells me he knew exactly what was in it.
If when you were in school you had paid me to do your homework, and I put a bunch of stuff in your homework that made you look silly, and you didn't proofread it before signing it and turning it in as your own work, would you still employ me as your homework do-er?