A lot of the times when people hear of Richard Stallman, or other people, who correctly state that all proprietary software is absolutely inexcusable, they feel pressured. Which makes them recoil and distance themselves from those types of ideas. If you need to suddenly re-learn the entire way you are using the computer, and you may have certain habits, or certain things you rely on, or enjoy very much, either games, or software, or in case of PewDiePie, the platform he is on. You will automatically feel like whatever these Stallmans are asking from you is so absurdly hard for you to do, that you don't even consider it. More than that, to protect yourself from that hard work, you come up with a bunch of reasons, to not even engage in that idea. Which creates an opposition. And it is not something that we want.
It's not just that, the overbearing FOSS mentality, from Stallmans corner of that world, is that you need to take a damn political position on software to be able to interact with other people that use it.
Which in itself is not actually true, but if you approach it like this with non-technical types then they will rightly and instinctively balk at both the software and you.
Bringing people to FOSS should be the same as bringing them to any other software, and if the ideology behind it is so self-evidently true then - by its own standard - it won't need significant petitioning to convince them they should use more of it for ethical reasons as well as to meet their needs. This is software, not Amway. They're trying to write a word document, not to join a cult.
