Unfortunately, there are people that take that "we really don't know for sure" comment as a negative as "proof" of whatever thing they are pushing instead. The internet is full of them.
I still think it's important that scientists be factual about the uncertainty, though. The alternative whacko theories also have uncertainty, so if we hold ourselves to that standard, we can also rationally hold them to their even greater degrees of uncertainty. When we try to pretend that a current theory is 100% certain and factual just to win an argument with idiots, it invites obvious and IMHO reasonable criticism of all of science.
Science is not a set of facts caved in stone. Science is a process; a way of thinking critically and exploring the boundaries of reality in a way that makes a best effort at getting closer and closer to the boundaries of the knowable in a rational and reasonably-objective way. It often makes missteps and corrections along the way, and we can acknowledge that openly while also contrasting it to non-science junk that isn't even on the right track.
