The intuition I've built is that you can't talk about a false positive rate being high or low on its own - it's always relative to the actual occurrence rate of positives in the tested population. E.g. if there's a 1 in 10000 risk of a false positive, but real positives also are only 1 out of 10000 tested cases, then a positive case will have a 50/50 chance of being a false positive (because for every 10000 tests, you'll have on average one false positive and one real positive). So a false positive rate can only be said to be low if it's significantly lower than the real occurrence rate of positives.