That warning was so common during the 2000's. Nowadays, it is like cat nip to me when I run across one. Does anybody still need to interact with one of these types of websites? Are you able to interact directly with it or do you need to utilize a virtual machine? I'm so curious.
If the website is really insistent about it, then I change my user agent to identify as the browser the website is demanding. No VM needed. I'm sure that there are some sites that really won't work well enough without using the demanded browser, but none of the ones I deal with are quite that crippled.