Not true at all. They're great fans - very loyal, just like Browns fans are. And Bills fans are also very generous. The Dalton phenomena where Bills fans donated $500,000 dollars to his charity in small donations, is just one example.
Remember, the late Ralph Wilson was the only NFL owner to vote NO on the original Browns move to Baltimore. IMO Bills & Browns fans are easily BOTH in the top 5 for best & most loyal fans in the NFL.
Bengals "fans" stay at home if their team is merely okay. BTW, NFL draft coming to Cleveland 2021.
https://www.cleveland.com/browns/2019/05/browns-and-cleveland-to-host-the-2021-nfl-draft.html