Well, caching content is not the same as copying it. The major difference in the court would be that caching is automatic - and as such you are not in complete responsibility of what it is you copied. If you do everything in your power to comply with any DMCA notices, then I couldn’t realistically see lemmy.world being targeted. This is an analogous situation to eg. accidentally opening a website containing illegal content. Sure, your computer did download the contents to the RAM, but what matters is that you acted in good faith and did not attempt to get the contents, it just happened in the process of browsing the web and as such you could not reasonably expect to receive such content.