What was incredibly strange about my situation was that it was initially a DNS problem, it couldn't resolve the addresses tha tthe hotel wifi wanted it to get to for the portal. I double checked, and basic DNS queries were working, just not those ones.

So I figured, I'll go on my phone, grab the IP addresses it's connecting to, stick those in my hosts file, and they'll get resolved. Well, this worked for the first portal address, but the one it redirected to couldn't be reached. Nothing I tried worked, so I had to do what I described above.