But ignorance is a thing, even for authorities.
There's a difference between a person/institution having no evidence of X, and no evidence of X in general. So, "who" doesn't have evidence, and how much effort they took to attempt to find evidence before they declared it non-existent, is a relevant question when "no evidence" claims are proposed.
It's funny, because when a person or institution comes out and says "there is no evidence" of whatever (without a context), it would be discredited if any obscure person in the world has such evidence, even if not widely published. It would, IMHO, be much better to say that "we have looked into <all the reasonable sources and literature> and found no evidence" instead.
Here’s an example of what that looked like in June 2021, covering developments in May, just 5 months after the first country in the world had approved the vaccine (UK, 2020-12):
https://www.yalemedicine.org/news/myocarditis-coronavirus-va...
Similarly Israel’s public health agency’s report was covered in June 2021:
https://www.reuters.com/world/middle-east/israel-sees-probab...
> The European Medicines Agency (EMA) said last week that heart inflammation after receiving the Pfizer vaccine had been no cause for concern as such incidents were similar rate to those in the general population.
The CDC and other agencies also continue to heavily downplay the risk as 'mild myocarditis.'
So what are you actually upset about?