Is he right?
You can post it wherever you want to, but a much, much better approach is to find someone who knows something about the topic and have her sit down with you and point out to you all the mistakes you have made, and suggest to you some books you could read to get a better understanding of the problem.
ADDED in view of comment by OP: It is, indeed, difficult for those who are "not in the academy" to get useful pointers for improving their understanding of mathematics. I would suggest that instead of starting with the biggest problems in mathematics, you start with the smallest. See whether you can solve the exercises in a textbook on computability theory, or, say, elementary number theory. If you can't do this, you know what you have to do; learn those topics first, before you even think about the big problems.
If/when you can work your way through the undergraduate texts in mathematics and computer science, then pick out some small unsolved problems. If you solve one, write it up, and send it to a journal. If you solve enough small problems, you will build up a reputation as a serious researcher, and those in the academy will pay attention when you announce that you have made progress on a big problem.
But start small. The people who have solved the big problems in the past --- these are people who worked their way up to the big problems, by solving dozens, hundreds, thousands of small problems first. I think that's the way to go.
No, I do not think that this question is on-topic for this site. The OP does not have much history here, so I am going on my general experience with proposed solutions to famous open problems such as P=NP that are posted on the internet. This answer does not refer to the OP in particular.
Too often, the people who produce these flawed proofs lack the experience to appreciate when their method is fundamentally flawed, and continue producing minor variations, which they re-post. As people begin to get frustrated, the tone of the discussion degenerates. The result is embarrassing for everyone, and takes time from more productive discussions.
So, for this special class of problems, I think that a realistic approach is necessary. By closing proposed proofs of famous conjectures, the chance we will miss a correct proof is extremely low. The chance that we simply avoid a protracted argument and frustration is far higher. Based on my experience with how these things usually go, I am willing to take that chance.
At the same time, I think it would be good to have a prepared statement that we could link to, so that we can explain to posters why their question is not suitable for this site. That statement could point out what someone should do if they think that have a proof of a famous conjecture.
There is no genuine question here. The user is well aware that these are off-topic on cstheory as we have told the user a number of times (and the last time quite explicitly)
discussing the correctness of unpublished claimed solutions to famous open problems like P vs. NP is not welcome on cstheory.
I believe this sort of question is on-topic for this site. It is about mathematics. It shows effort. It inherently provides context. However, I think some humility is in order when asking such questions. Someone just starting to study such a deep problem who believes zie has found a proof might be better served by asking what zie did wrong rather than whether others can verify zir proof is correct. In the highly unlikely event that someone should post a correct proof here, that will likely be recognized quite quickly and the modesty of the question will not limit the accolades.