why can't edit Ur's answers?

Why can't edit Ur's answers here - i made an answer , but i didn't understand question correct ,

later i reread question , and understand that i answered wrong - since it was at "Irc.lv" section -

but i can't edit it any more ;( pretty annoying!

hah i know that i need undarstend it from first time or try read it correct - and post only when u r asure , but still there shold be
chance to "Edit" ur's asnwere - u don't agree?


Regards,
Mak