Is it possible to detect which nodes have applied this patch because I think if every node did it we could remove ordinals and the problems they bring to the Blockchain?
Theoretically it's possible, but who knows how reliable is it. You can initiate connection with any full node, then send "mempool" message[1] which ask list of unconfirmed transaction. After you obtain the list, you just need to check whether it contains any Ordinals TX. Or just ask Ordinal TX data using "getdata" message[2].