One does not have to agree with an opinion to defend an individual's right to it. The people who are so quick to defend Leak & Pickering's rights were silent when Yassmin expressed hers.
I'd imagine because Leak and Pickering were the subject of potential legal cases against them. I don't think anyone suggested any sort of legal argument against Yassmin. If they did it wasn't taken seriously (and rightly so).
Telling someone their argument is s**t is not an assault on freedom of speech. Using the law to seek some sort of penalty is.