It is sometimes like this:
post 1(user x): News about update?
post 2(user y): No, because ......
post 3(user z): UPDATE?!?
So for me any user is lazy if he didn't read the OP, skimmed what it's linked in the OP or skimmed through the the current page and 1-2 page in past of the thread. From the most asked questions most of them wouldn't needed to be asked (again).
So, in my eyes not only an user classified himself as lazy but also shows some lack of common behaviour.
And question back: If it cost you less than 5 minutes to wrote the answer, why should the questioner not invest his 5 minutes to search for his own answer?
It would shows for me, that the user is modest and valued our time the same as his own.