If you're prepping for end-times, [or as in the case with another subscriber here, you feel like you need to do something drastic to stop the "impending" event from happening,] you need to get mental help. = "If you're prepping for end-times, you need to get mental help," grammatically speaking.

So you're saying anyone who believes the world is going to, or would, end, is mentally ill. Regardless of whether or not people who believe this are correct, your contention is nothing more than an unfounded assumption. Additionally, it reeks of a sort of accusation that would be spouted by someone in denial, which is, ironically, a symptom of irrational thinking. This becomes abundantly obvious when one considers that you are a person who apparently does not believe the September predictions to be valid, yet here you are in a subreddit dedicated to these predictions, presumably with the sole intention of telling people who believe in these predictions things like "you need to get mental help," presumably to validate your feelings of denial. In a way, this is a form of projection. On some level, it's possible you are aware that your feelings of denial are irrational, and therefore feel the need to cast the blame on other people - in this case people who believe in the September predictions - by insisting they are the ones who are irrational, or "need to get mental help." Again, whether or not these people are correct is completely irrelevant. This is specifically your fault in thinking.

It's beyond "not normal."

The normalcy of theorizing that catastrophic events will happen in September is irrelevant to the validity of these theories. In fact, to imply that the supposed abnormalcy of making or believing in these theories has any bearing on whether or not they are valid, suggests you base things you personally believe on how "normal" that belief is, which is again, laughably irrational. It suggests you are a person who makes decisions based on emotion rather than reason, and therefore you have no place in this - or any for that matter - discussion, until you remedy this flaw in your reasoning.

It is mental illness, plain and simple.

To say that something is "plain and simple" does not validate your argument, nor does suggesting something is obvious compensate for the lack of evidence to support your claims.

The scariest fucking thing in the world is a person who feels like they have nothing to lose & decides to act on it.

This is just a meaningless cliché intended to add emotional weight to your contention, in an attempt to compensate for your lack of logical reasoning and evidence. It is the footnote of an emotional, irrational person.

Before you completely dismiss everything I've said, which your personality suggests you will do, ask yourself "Why do I take time out of my day to venture over to a subreddit dedicated to something I don't believe, to argue with people who do believe that thing?" The answer is: it is to make them wrong, because you don't want the world to end. The fact that you refuse to see this is mental illness, "plain and simple."