It's exactly as you describe it. They do have their own ideologies. I wouldn't say “coherent”, but often they have a foundation, anyway. In an attempt to make it more appealing to a broader audience, they will glom on to, if you will, those very typical, normal, banal, everyday kinds of grievances or anxieties, whether they're economic, cultural or even physical in terms of the threat of crime or in this case in the context of COVID, which is the threat of disease.
They will exploit those narratives and often explain them through the lens of race or immigration or gender, even. I think that's where the danger is of bringing unsuspecting, unintentional people into the movement.