UserAgents while odd do give the webserver some knowledge of the client capabilities. Try setting your UserAgent to ie6 and see how much of the internet breaks.
Most sites will do live inspection of browser capabilities rather than using the user agent to grok capabilities, simply because user agent is hardly reliable.
The user agent language is because reddit requires bots to have a custom user agent identifying the bot when using the API. I don't think it's about browser capabilities. This is the screen they give to unknown bots, they must have adjusted rules to count any IPs registered to a cloud/hoster or VPN as a bot by default out of paranoia of third party apps and scrapers.