"Or" has its usual meaning here — as far as I can tell. Is there a subtlety that Chinese speakers are able to pick up on? Please let me know, because you’ve stimulated my curiosity. In Chinese, I sometimes have to think hard in order to avoid confusing 或者 and
Other ways to phrase your sentence would be:
Alternatively, they just don’t have the patience….
Another possibility is (that) they just don’t have the patience….
Edit: We would need more context to be sure, but it could also mean “on other occasions”: “On other occasions, people just don’t have the patience….”
If you'll tell me more about your confusion, it may be easier for me to clear it up.