My take is that SeanLuke quoted a contentious description of PV's activities. wnevets said the description was an outright lie. ifyoubuildit asked for details. rootusrootus responded that the description implied neutrality, and said they aren't neutral because they target and slander one side particularly. sourcegrift gave an example of other media not being neutral. Then you said that media aren't obliged to be neutral.

Slander was only relevant insofar as the slander evidenced a lack of neutrality. But the lack of neutrality was never truly relevant in the first place; rootusrootus erred when he said the description quoted by SeanLuke implied PV is neutral. BurningFrog and streamer25 were correct in pointing this out. Describing PV as journalism doesn't imply neutrality, nor does anything else in that contentious description.

You also erred when you assumed sourcegrift considers mockery to be slander. From the context of the conversation, I think it's clear that sourcegrift considered the mockery to be evidence that the rest of the media lacks neutrality; in other words sourcegrift was correctly disputing the supposed contradiction between partisanship and journalism. Journalists aren't neutral; journalists mocking people with plain partisan bias demonstrates this.