to me, it seems some Titans fans look at Fisher's antics as an "F U" to the franchise and fanbase that has supported him for 16 years and that has to watch the poor product Fisher has put on the field this season. Then his comments afterwards basically saying he doesnt give a crap what those people think, and telling them "they need to rethink things" probably added to the disrespect for some.
as far as charity, a lot of coaches and players all around the league participate in charity events. Some of them set up their own charity events, yet you dont see such antics. You can support a cause without disrespecting your franchise all for charity.