Anyways, I'm sure you can understand why a political event, where many of them do rely on RFID access badges for certain personnel to enter certain areas, would not want someone with a device that can clone badges.
If you go to a political event like that... just take your actual key. Not a device that spoofs your actual key. What you're proposing is essentially saying you have a legitimate reason for carrying around a lockpicking set, because you use it to enter your apartment when you forget your keys. It's pretty understandable there are high-security places that won't let you in.
All modern automotive and smart apartment keys can't be cloned that way. You can't do simple replay attacks.
Are you talking about some cheap office RFID badge or something?
Because if you have any important keys for things you own that can be cloned with a Flipper, you should be upgrading them to prevent that.