It is a major issue. People need to be able to play and tinker. As a child/teenager I didn't have money to pay for servers online but I still wanted to mess with that stuff.

My ISP didn't enforce the no-servers rule so I was able to run home servers but you shouldn't have rules that violate net neutrality that you "choose" when to enforce. People need to be able to tinker and figure things out without artificial restrictions that exist purely so that they can claim to not have bandwidth caps. It's borderline false advertisement and a violation of net neutrality.

This doesnt stop you from tinkering or anything of the like. Its meant to stop a business trying to piggy back on a residential service. Just feed their FAQ

https://fiber.google.com/help/ : Can I run a server from my home?

  Our Terms of Service prohibit running a server. However,
  use of applications such as multi-player gaming,
  video-conferencing, home security and others which may
  include server capabilities but are being used for legal
  and non-commercial purposes are acceptable and encouraged.

It sorta allows you to kinda tinker as long as Google doesn't decide that it's bad. Until they do.

You expect people to read?

Silly me.

It's because it runs contrary to the concept of net neutrality -- ISPs are dumb pipes, and trying to differentiate between different "traffic patterns" can only lead us down a very dark hole of no return.

This has nothing to do with net neutrality or traffic patterns. Its a service agreement that says you are not allowed to run a commercial server on their residential service.

...how is that not a net neutrality issue?

because net neutrality is about all packets being treated equally. This is a service agreement.

One is a piece of paper and the other is network technology. Can you guess which is which?

What happens when you are caught violating the TOS?

The point of net neutrality is that any Internet connected computer should be able to communicate with any other Internet connected computer, without having to pay surcharges or extra fees, without limitations on protocols, directions, purpose, content, etc. It makes no difference if you are being restricted by a contract or by a technical system. If you are unable to host servers using your Internet connection you are not enjoying net neutrality, regardless of why you cannot host servers.

You will probably be warned then future violations will probably lead to a contract termination. Neither of which has anything to do with treating all packets as equal at the network level.

Sending email spam, downloading child porn, etc, etc also violates their ToS. However just as long they as treat those packets the same as any other packet they are network neutral.

Is there a difference between, for example, banning Netflix traffic on the network level and banning the use of it in the TOS?

In the eyes of network neutrality, absolutely.