I’d agree. And because verbosity is one of my weaknesses I’ll talk a little bit more about this.
I see the concept of “bad writing” thrown around to the point where it has next to no meaning in that people tend to view it as a cheap substitute of “I didn’t like this.” However, at the same time, not every “this is bad writing” claim is an “I didn’t like this.” Bad writing does exist. To an extent it’s absolutely subjective, but there are general concepts that most people would agree are not good writing. One of the concepts that is generally considered bad writing is misleading your audience.
Red herrings/bait and switch is a trope, however, and most tropes are tropes because they are often used in good writing. But a trope by itself is not good nor bad writing. A trope can either be seen as trite and pointless, or excellent, depending entirely on the execution of the trope.
Bait and switch, or red herrings, can be either good or bad. They generally work well if and only if you have an equally or preferably, even more so, satisfying option to appease your audience. Like “you were wrong, BUT HERE IS SOMETHING BETTER.” If you don’t, your audience will feel misled.
Being tricked but finding out the alternative is even more satisfying, though, is completely different. Deliberately misleading your audience without a more satisfying reveal comes across as… not awesome writing and you run the risk of alienating your audience by treating them like lols. Of course, no creator should be indebted to their audience and fandom entitlement is like, a legitimate thing that’s really creepy and disturbing to see, and teasing is all good, but if you’re deliberately building something up and don’t have something satisfying for your audience, that’s… not going to end well. Especially in a serial story which in part thrives on speculation and hype, of which theorizing is a part, you really don’t want to risk your audience thinking there is no point to theorizing anymore. (Overthinking is often a thing and tbh I don’t think BNHA is that deep of a series, but you definitely want your story to, like, make sense and satisfy as many as possible though it’ll never please everyone.)
At this point regarding the Dabi Todoroki theory, I can’t think of what would in any way be an equally satisfying or more satisfying option for Dabi’s real name and/or what happened to Touya. I can’t say that that cannot happen, though, because you never know, but I think things are just too heavily hinted at this point that I genuinely can’t think of something equally satisfying from a narrative perspective. We’ll see, though.