The last paragraph in the article literally indicates there is no causal relationship or proof of any direct link between the vaccination and myocarditis.
> "Finally, we cannot provide a definitive functional proof or a direct causal link between vaccination and myocarditis."
1/3 to 1/2 is a tremendous exaggeration. In Latvia it is ~11%, in Estonia, close to 5%, and in Lithuania, next to non existent.
The predominantly ethnic Russian who were living in the SSR of Latvia or Estonia, but were not Latvian citizens before 1940, and who have not learned the language and acquired citizenship after '91 have rights, but cannot vote or hold some political offices. Same with any other foreigner. They can learn the national language and apply for citizenship. Choosing not to doesn't mean they are treated poorly or unfairly.
There is no unilateral renunciation of citizenship. The tax treaty between the US and the Netherlands has what is known as a 'savings clause', which basically states, regardless of what else is in the treaty, nothing will stop the U.S. from taxing the US person based on US laws as though the treaty did not exist, except for specified circumstances.
> "Finally, we cannot provide a definitive functional proof or a direct causal link between vaccination and myocarditis."