The player gets attacked by mobs immediately after spawning into the Nether or Overworld when exiting the Nether portal. This makes it impossible to visit the nether since you get attacked and die before you can even get a chance to fight back.

If Mojang replys with this is intended game play, then this means Mojang wants visiting the Nether to basically be impossible if you decided to reuse the same portal to visit another dimension. This is so frustrating, and makes survival Minecraft basically impossible.

To fix this, you should get a few seconds of invisibility when exiting a nether portal. If this isn't fixed, then survival Minecraft is basically impossible.