Whether it's considered rude or not depends on the context and the nature of your relationship with the guy. Let's consider a few scenarios:
Established plans: If you both had solidly agreed upon plans in advance and he hasn't communicated at all to confirm or cancel, it can be seen as inconsiderate and disrespectful of your time. In this case, it's reasonable to feel concerned or frustrated.
Casual plans: If the plans were more informal or tentative, and there was no firm commitment made, then it might not be as rude. Sometimes people can get busy or forget to follow up, but it's still considerate to communicate if something has changed.
New relationship or early stages of dating: If you're still getting to know each other and the plans were not set in stone, it's possible that he might not realize the significance of confirming. However, it's still good communication etiquette to check in if plans were discussed.
In any situation, open communication is key. If you feel uneasy or uncertain about the plans, it's okay to reach out and ask for clarification politely. You can say something like, "Hey, I just wanted to check if we're still on for our plans today?" This gives him an opportunity to respond and confirms whether the plans are still happening or if there have been any changes.
It's important to remember that everyone's communication styles and habits differ. Some people might not be as prompt with texting, but that doesn't necessarily mean they are being rude. However, if it becomes a pattern of unreliable behavior, it's worth considering whether this is the type of person you want to continue making plans with in the future.