Yes but when it comes to stis, their attitudes do affect you. For example, their hysteria around stiS based on myths their granny told them can often mean that if you fuck more than they'd like, if you choose to not use barriers for some sexual activities like oral sex or if you have something like herpes, they treat you like dirt. Lots of people would forbid their partner to have sex with anyone diagnosed with herpes, even with strict condom use with no scientific evidence for doing so. Yes, that level of ignorance does bother me. Particularly if a partner or metamour is the ones displaying it. It would be like someone openly saying things like if you touch someone with HIV, you'll get AIDS. That would just be based on total ignorance and I hope anyone who heard someone say something so stupid and harmful would step up and say something.
If you trust that your partner wouldn't fuck someone without a condom if they hadn't had the sti talk, you're "apathetic" rather than having a healthy amount of trust in your partners concern for your wellbeing