I don't really want to give this jackass the dignity of a response, but for anyone actually curious vaccine myocarditis is significantly less severe than myocarditis from the coronavirus and other viruses. Prognoses are excellent and people recover in a couple of months. From what we can tell it seems to be a susceptibility that some people have and likely they'd fare even worse against the antigen from the virus given the virus can replicate, is not just the spike protein, but the whole virus arrayed with a crown of spikes. In any case too myocarditis rates from coronavirus infection are higher than from the vaccine. Even for young men. And again more severe with worse prognoses. And that's just one aspect of the virus' harm.
I'd also just add that vaccine side effects emerge shortly after vaccination- within the first ~8 weeks. The vaccines themselves don't persist in the body. You aren't going to suddenly have a vaccine side effect emerge years later. That doesn't happen. As such it is vanishingly small this is related to the vaccine. Young people can go into cardiac arrest. Happens to young athletes all the time.