Looks like 1200 people in the last year. 1200 / 350e6 = 3.4 micromorts.
By comparison, getting out of bed at age 45 is about 6 micromorts.
The UK have about 13,000 arrests per year over social media etc. Without litigating all 13,000 of them for validity, that's about 185 microliberties.
Birth control is about 1-5 micromorts.
So you're 30x more likely to be arrested for a social media post than death by getting out of bed, and 55x more than being killed by police. And it's in the same range as taking birth control.
Realistically, these are population estimates. Your actual risk of dying by police is highly correlated with the number of violent interactions you have with them. If you're a getaway driver or a bank robber vs SW developer, you probably have significantly different risk profiles.
On the other hand, edgy social media posts are potentially much more diffuse across populations.