It's not just individual scientists (who certainly aren't going to seriously entertain every crank they encounter - that would be insane), but institutions that

It's not just individual scientists (who certainly aren't going to seriously entertain every crank they encounter - that would be insane), but institutions that hire based on expertise, consider which papers to print based on expertise, and so on. In science & other expertise-driven fields we assess competence & credibility when hiring, judging proposals, tenure, awards, research, etc. CVs & history are relevant and considered. That's the way an institutional expertise-driven domain like the sciences works.