The person checking the latch is taking seriously a failure that has not happened.

Imagining a bad outcome and acting on it looks unnecessary from outside every single time. Someone who goes back to check a gate is treating a small possibility as worth two minutes, and the value of that only appears in the version of events where they were right. Being called anxious and being called thorough often describe identical behaviour. Which word gets used depends on what happened afterwards.

Give the careful people around you the benefit of the doubt rather than teasing them out of it. Where your own checking has stopped helping and become a loop, agree on one check and let that be enough.