If someone is reliable and trustworthy in their communication, then calling them "toxic" because you don't like the style is just wrong.
Conversely, someone can tell you all day every day how honest and straightforward they are, but if they aren't consistent or trustworthy, then their communication style is irrelevant.
Such behavior fails to offer the report a fair chance to know what's expected of them and, presumably, how they're not meeting those expectations. It has much more in common with the kind of dysfunctional communication you see in unhappy marriages, than with anything I require of a manager - or, should I eventually join management myself, with anything I'll provide my own reports.
That's what "toxic" is a shorthand for. Yeah, I'll grant it might be consistent. But to be consistently bad isn't, you know, not bad. Being able to predict the bullshit that is going to happen doesn't make the bullshit not happen. It just means you can see it coming. I'll concede there may be reasons to tolerate it, if the benefits of the job outweigh the bullshit. But that doesn't make it not bullshit.
(And, as a side note, anyone who talks about how honest or straightforward they are - that's a big yikes from me, chief. People who are legitimately honest and straightforward don't need to talk about having those traits, because their behavior reflects them. People who do need to talk about having those traits are, in my experience, very likely to be trying to cover their lack.)
At best, it is someone who is scared to have difficult conversations. At worst, who knows.. I've slowly learned not to try and rationalize what makes people like that tick. It's their issue, not mine.