Really slow main page load

When I goto the main developer community page:

https://community.intersystems.com/

When I turn on network monitoring this root page takes over 6s to load, this is with the other pieces of the page already cached on a nice fast network connection, the by the time the other requests are made it is at around 6.7s! A few other attempts were slightly better at around 5s. By comparison if I look at stackoverflow.com I see the browser completely done in <1s, the content itself takes just 433ms.

How can be get this >6s down to something a little more reasonable like <1s, even 1s is pretty slow these days.