Right - which is why a personal use server such as your home music collection or Roku, or a COD server on Xbox is fine. Email for 500 people, running the next eBay, or co-locating boxes for people, isn't.
I agree. Which is why most TOS make sense when aimed that way. Sadly some ISPs find it easier to make broad legal strokes to cover their backsides later on.
For example: I run my own email server from my basement. Who uses it? Me. Maybe my dog... but mainly just me.
Yes, it is technically a server, so yes technically my ISP could shut me down... but with a daily throughput of what, 10mB? I doubt it.
Nor does using/having/needing/running a server imply business use.