Players in Spectator mode cannot access the Nether or the End dimensions

When in Spectator Mode, a player just passes through a Nether or End Portal as if it's not there and active. I'd expect to still be able to access the other dimensions even if I'm in Spectator Mode.

How to Reproduce

1. Build a nether or go to end portal
2. Activate Portal
3. Switch to spectator mode.
4. Go inside the portal.

Observed Result
You cannot enter their dimensions in spectator mode.

Expected Result
You should.