The sheet music sold by mainstream publishers is almost always completely useless if one wishes to learn a guitar arrangement. Therefore, regardless of any abstract idea about the artist's right to be compensated, the big-biz music corporations have to right to surpress distribution of tablature that conveys information not available elsewhere.

On the other hand, most of the so-called "tab" sites I've found on the internet do not provide tablature at all ~ just chords! And, as often as not, incorrect chords!

The good, useful tab sites are few and far between, and it's a shame to see them disappear due to threats of prosecution by the greedheads of the big music companies.