Ian has had a long term plan in mind from the start, and that included a certain sense of branding. Even 10 years ago, when politics were not nearly as toxic as they are now, he was aware that politics were, by their very nature, divisive; further, he made the conscious decision to make his public persona that of a firearms scholar, and just that. People know what to expect of him.
That's exactly the issue with Karl: no one knows what to expect from his content. I was subscribed to InRange for a while, but then noticed that for every good gun video, another 3 completely unrelated to the topic came out as well. Independent of my personal leanings, I don't go on YouTube to be lectured about what's right or wrong; I just want to watch cool shit and learn. That's why I unsubscribed from InRange, and continue to follow Ian in general.