Not accused. It actually does cause it in a small number of people.
Myocarditis With COVID-19 mRNA Vaccines - PubMed
Myocarditis has been recognized as a rare complication of coronavirus disease 2019 (COVID-19) mRNA vaccinations, especially in young adult and adolescent males. According to the US Centers for Disease Control and Prevention, myocarditis/pericarditis rates are ≈12.6 cases per million doses of...pubmed.ncbi.nlm.nih.gov
12.6 cases per million among people who should not have been given the jab in the first freaking place. That is what I find an atrocity. In that age range, there is very little chance of getting more than weak symptoms from COVID in the first place.