I’ll be emailing the site admin… or some contact at the site, but, is there anything else that can be done to try to put pressure on these websites that tell me “you’re not getting the best experience… download Chrome.”?
I know Firefox has a “Report a broken site” feature, but, the site isn’t technically broken. They’re just telling me to switch browsers.
The notice means they know about the problem but don’t care enought to fix it, probably because of economic reasons. The only “pressure” you can exert is to try to make them care again, by not using their site and by promoting Firefox to your peers.