There shouldn't be any "should" about it. I think the broadcasters who didn't wear one should have lambasted as bullies those who criticised them for it rather than falling in line. We shouldn't be under pressure to display our beliefs and affiliations in public, even if it is a belief whose opposite is considered politically incorrect. I'm not under any pressure to go around displaying icons to say that I'm against paedophilia or in favour of any other widely supported charities or movements. So why should I be under pressure to display an icon showing I am in favour of this one? Absence of an icon of support should not be interpreted as being against it. Conformity to a norm is what goes on in totalitarian societies, and we should aim to be free from that.