Proselytization refers to trying to convert someone to a religion, which they don’t do.
They do claim it’s a religion. It is legally a religion. When they are recruiting, it is proselytism. Also, proselytism is part of the definition of a church in most countries, that is why, for instance, the Church of Satan is not legally a church in the US, because they do not proselytize. By their own saying and by the government, TST is a religion and they do proselytize.
Where did I say they are a non-profit?
You said it is just an NGO. I mean, yeah, but you could say that about pretty much anything. But clearly there is something more to it than the average NGO, with them being both a church and a couple for-profit organizations.


Well, here and now, with the original comment asking to join them. I do have some anecdotes but they aren’t really relevant here, I guess.
Here is the CRA rule and the IRS one
Both state that “advancement of religion” is a requirement, which is quite close to proselytizing (promoting and manifesting religious belief).
The thing is that both countries were funded by christian people, so their definition of religion is biased towards it, so you can’t really have an individualistic religion like satanism be recognized.
We can also note that Canada is discriminating against non-theistic religions and asks quite explicitly to “support and maintain missions and missionaries to propagate the faith”. Canada is still a religious state, after all.