This is a sad tale.<p>At best, the competitor has behaved very poorly. Their removal of copyright claims in particular is a clear indication of malign intent.<p>But the author is correct in their assessment: the primary purpose of the GPL, and Free or Open Source licenses in general, is to provide a right to modify and distribute to anyone who obtains the software. There is no special protection for the original author(s).<p>Many projects have had a similar experience. Retaining a trademark on the project name gives the holder some parallel rights. Even projects as significant as Linux have had to deal with this.