it's the weak who invite violence

"He’s not to be located either here or there, because, strange as it sounds, there is no single point on earth he could claim to be his home —he is pretty well everywhere. Of course there’s no name, no past, nothing, just muscle pumped up with hatred. But while there’s any weakness left on this wretch of an Earth, his kind will persist.Yes, it’s the weak who invite violence who are the probleme."


While I was reading this article, I paused for a few moments at this part "it’s the weak who invite violence who are the problem." The verb invite should be followed by s, shouldn't it?

No. "The weak" here is a collective term, so could be replaced with "they". In the same way, we say "The dead walk the earth".