@Adam_Woodbridge @AE67 @garym and others:
Before I start, I need to say that while I understand what the opposing argument is, I am not endorsing the impact of these comments on sound quality.
The claim here is not that the digital bits on the cable (via the Ethernet frames -> IP frames -> TCP packets) are being altered. The claim, especially in regards to ground loops, is that the ethernet cable is connecting the ground of power going into the switch and the ground of the power going into the device. Thus, you have a system that has “2 grounds”. It is then further claimed that these ground loops, using the hardware given, produce a notable hum or degradation of quality in the D->A conversion, or even later in the chain in analog.
If someone claimed that the bits were being altered and this was impacting audio streams over digitally reliable protocols (in a way other than skips or pops), I would delete that post/topic, because that would be entirely bullshit.