Myocarditis rates are something like 30x higher in COVID infection cases vs. vaccination. So even if this phenomenon was real 1) you'd have to rule out it actually being because of COVID infection, and 2) the baseline for "it wasn't like this before" should compare to what happens with the statistically inevitable infection with COVID vs. in the presence of vaccines.

The reality is we have COVID, it's not going away and the effects are far worse, so this is the control scenario now.