Politeness is not a supreme virtue. These people have already proactively disrespected others by invading their privacy - they simultaneously sacrificed the right to be treated politely. Would you respond to a home invader with a polite request? If not, then we've established that there are situations in which politeness is not required or justified, and now we're just quibbling about which actions justify which responses.

> You've[...] made it easier for the intrusive human being to continue to rudely intrude on others

If you have made them feel uncomfortable - perhaps forced them to stop and confront the discomfort that they are selfishly causing - then this is not, in fact, true. And if this happens repeatedly, they will stop.