"You don't need windows for gaming, 90% of games work on linux!" -- except the 10% that DON'T are all of the new, massive titles that people want to play. It's like saying "90% of the gears in the car work fine, just not 1st gear".
"There are 0 driver problems" -- obviously not true as some hardware only ships with windows hardware. Yes it's true your new network card or mouse won't have issues, but a lot of hardware simply doesn't have support, and a lot might be supported if you spend enough time fanagling.
"it's just as easy use as windows or mac" -- until you need to change one of many settings that hasn't been included in a control panel, because linux users have been more than happy to drop to config files and cli usages to tweak things (i.e. lots of stuff left out of system GUIs)
I don't know why people do this. Especially in communities that are technical (and thus tend to be "technically correct" about things), why people essentially lying (by omission, if nothing else) about Linux?