Sickness from the shot is not my main concern. I'd love to see the whole risk profile for my case. I have a feeling that governments are doing "booster for everybody" for political reasons. They don't want to single out particular age group.
The only conspiracy I can at least follow along is the one where government is funneling money to their buddies at evil BigPharma, however there are plenty of easier ways to do this than a nation-wide vaccination campaign.
There is a strong argument that boosters are pointless for young people (or even bad due to small myocarditis risk for young males), but politicians are scared of making mandatory vaccinations for 50+ only.
(Based on an interview with a well known sociologist)