You should only respect people who respect you back.

For example, US and UK conservatives for some reason coff coff hate Sadiq Khan, the mayor of London. Why, you may ask? Well he's a Muslim, and a liberal, who has always supported and voted for LGBT rights, and believes multiculturalism can work (he's the proof) so long as there is mutual respect and tolerance. The word here is mutual.

It does not mean he likes the LGBT community, that's neither here nor there. He probably doesn't hang around gay bars. But he supports their equal rights, so long as LGBT people support rights of others too.

If a group of people, such as fundamentalist Muslims for one example, is intolerant, disrespectful, and unabashedly so, or even violent, towards other people, we as liberals should absolutely not defend them in any way. They are anathema to what liberal means.