I'd boo him. I care too much for this club to watch something like this silently.
Different mentalities I guess. Here, people don't just clap and go merry whether your team wins or loses like in the Northern countries.
My hometown team Halmstad beat Helsingborg (coached by the god of Helsingborg and Sweden Henrik Larsson) during last season which sent Helsignborg down from the top division Allsvenskan and sent Halmstad back up to Allsvenskan, after the game some fans stormed the pitched and ripped off the shirt of a Helsingborg player, one fan even tried to punch him in the face. The player was Jordan Larsson son of Henrik Larsson (neither of them stayed in their hometown club after that)
A player from my hometown team scored an own goal last year which sent the team down from the top division, he and his family got death threats sent to them even his child who was 5 or something at the time. My hometown club is a small club, has like 3000-4000 people per game if we are lucky.
AIK supporters have been known to storm the training grounds of the first team demanding answers for their current bad forms or other questions they have, even going as far as threatening players, coaches and other club staff which results in people leaving the club fearing for their life.
Football in the north is as crazy as everywhere else. That kind of behaviour is something i will never support, booing and otherwise harassing players, coaches, other fans or club staff is something REAL supports do not do IMO. Sure its a big step from booing to threatening players but still just childish mentality IMO.
FYI Sell Gomes he does not fit BARCA