So? If they still power on and are capable of talking HTTP over a network, and you don't require the transfer of data that needs to be secured, why shouldn't you "let" them online?
Usually browsers on hobbyist legacy operating systems, to which modern browsers haven’t or can’t be ported, not to mention keeping root certificates up to date. Or even if they do support SSL, then only older algorithms and older versions of the protocol. It’s nice to still be able to browse at least part of the web with those.
The problem is usually SSL support, the problem is that older SSL and TLS versions are being disabled.
I actually have an example myself - an iPad 3. Apple didn't allow anyone else than themselves to provide a web browser engine, and at some point they deliberately stopped updates. This site used to work, until some months ago. I currently use it for e-books, if that wasn't the case I think it by now it would essentially be software bricked.
I acknowledge that owning older Apple hardware is dumb. I didn't pay for it, though.