Why wouldn’t other countries just not sanction us?

Because the vast majority of countries are dependent on the USAs financial system, odds are very good your country is dependent on that same system in thousands of ways. Especially Europe.

They hate America even as they depend upon it... and it's even worse than that, as the USA is controlled by banking interests that have been around since the slavery days. Should America disappear tomorrow, another "financial center" will replace it, it's an international web of financial interests.

Their only goal is profit, national concerns are irrelevant to them.

The USA is not part of the ICC and does not recognize its jurisdiction.

https://asp.icc-cpi.int/states-parties

These are the states that signed the Rome Statute.

I think they're all too reliant on the US and they notice, the US kinda has them by the balls, strategically. They all seem to be quiet quitting / ghosting, and that seems to be all the power they have. What they're doing will be felt for decades, it's more of a slow burn, they are kinda sanctioning, in the sense of removing reliance of all US products. The US govt has built itself up as an evil superpower, with tendrils of control over other countries, military posts, strategic assassinations. What do they have on Australia, that makes them defund supports for disabled people, just to be able to bomb Iran along with the US. There's some deep seeded control going on there, and in many other places.

Russia is already sanctioned/sanctioning due to the Ukraine War. China maybe could, but they are more focused on renegotiating a trade deal. The EU is already in the process is strategic decoupling and can't go that much faster. Any other country is likely going to either have enough economic consequences that they can't afford to or are doing so little trade that it doesn't mean anything any way.

I guess the closest thing to this that's happening is BRICS and their efforts to do less international trade in dollars. De-dollarization freaks out the US ruling class, so you know it's a good thing. Just wish it would happen faster.

China and Russia are not members of the ICC.

Also most of them are pretty happy that Trump is busy bombing Iran and not them. But also all of them are lowering dependence on the US as much as possible, but are quite about it. At least the EU also does not like the Iranian regime terribly much.

Sadly, EU is too much depending on the US. Just think about Mastercard and Visa.

The U.S. is very powerful. It has the third biggest population in the world and has a lot of economic influence, including all the damage trump has done to it.