Absolutely. There is no point in trying to fight it by blacklisting tor, that is my point (well, one of them).
As You have noticed, we have also been spammed from other sources, like China.
There is not point, we cant prevent it from happening, but we can minimize it by making it harder.
The clever spammer, or professional if you want, dont need tor, and probably is not even using it.
Any proxy will do even better.