but I do notice there is a passion against Xbox on this site.
It's not specific to this website tho. I am in several forums all accross the globe, and there is always the same issue: moderators asking people to stop bashing/making fun of Xbox fans, one of my favourite forums has its Xbox section locked since yesterday to "clean up" an ban users who are not really fans of the brand.
I think the issue is more widely spread that we can imagine.
I think it's mainly a matter of XBox being the least popular of the three consoles (objectively in terms of sales). That leads to more users for the other platforms. That means they can attack without much fear of reprisal, and will generally be supported, whereas if you insult Sony of Nintendo, you're more likely to get shot down. There's also the factor that Sony and Nintendo are older companies in terms of gaming. A lot more people grew up with Nintendo or Sony than Microsoft, and the passions you form in childhood tend to be stronger. Plus, Microsoft is the richest and most powerful of the three companies, and to some people that is a negative.