But "frontier" mathematics is still a highly advanced, highly specialized field. It can take years of study to be prepared to understand the established theory and results for a given subtopic.

These two observations, taken together, lead to the predictable outcome of a lot of math "enthusiasts" with an incomplete understanding of the field loudly asserting that they have discovered a radical new result. Often they lack the foundation to even understand what they are doing wrong.

The reluctance of mathematicians to engage with amateurs that come off as cranks is a symptom of how accessible the field is.

I haven't had any interaction with mathematicians that I would describe as hostile.