This is the point. These things are canonical - even if they don't necessarily fit in with the rest of the canon - because they are officially sanctioned. That's what the word means - canon is determined by the church or an authority. Everything in the Bible is canonical, but that doesn't mean it all makes sense from beginning to end or bits of the Bible aren't contradicted by other bits - they are. Anything you come up with to do with Transformers that hasn't been dictated by Hasbro or its affiliates is fanfiction. It could theoretically become canonical, but it isn't at this time.
What you're talking about in terms of streaming clashes in various universes and franchise is about continuity, not canon. You can come up with your own personal continuity, but you can't have a personal canon.