The social contract for putting a website on the public internet involves following standards and making your website accessible. You SHOULD make sure that your website is readable to people no matter what user agent they are using as long as it's standards compliant.
For example, making a website that only works in Edge and refuses to load for anything else would be a shitty practice. You are free to do it. There's no one stopping you, but you should expect people to bitch about it and they might think you're kind of a jerk or maybe just bad at making websites. It's the same thing when a site actively rejects traffic from curl, wget, or any other common utility that many people find useful.
For example, making a website that only works in Edge and refuses to load for anything else would be a shitty practice. You are free to do it. There's no one stopping you, but you should expect people to bitch about it and they might think you're kind of a jerk or maybe just bad at making websites. It's the same thing when a site actively rejects traffic from curl, wget, or any other common utility that many people find useful.