As a forum available to the public and with answers searchable by Google/Ecosia/Bing/Duckduckgo etc, we do have to be careful because posts are considered to be "published". It's up to the owners - who appoint moderators to fulfill the task - to ensure that posts either comply with the law, or are removed. We do have the power to edit a post, which I have occasionally done to change a title so it's spelled correctly to aid in searching, but we can also edit the content of a post if the majority of it is valuable, on-topic and not contrary to our rules.
Which, I should add, starts with "family friendly" - the main goal of this forum is to provide help for people with Nissan Navaras, but we don't mind if Pathfinder owners jump in now and again since they're mechanically so similar and suffer the same problems (except that rear coil suspension, now I'm going to have to get upset over that). We don't think there's a lot of ground gained if posts are adversarial/antagonistic towards other members, but you can understand taking a swipe at a poor experience with a supplier or service provider, as long as it's "reasonable".
To that end, I could completely understand if someone posted "Bill from GoneSoft Tyres reckoned he couldn't touch my wheel alignment because my air filter was dirty" - it's reasonable, because while it names the business, it doesn't do it in a derogatory way and states what we can assume is facts. If it said "That dirty slimebag Pete from Zapper's Auto Electrics changed my indicator bulb and tried to charge me $1700" then it's more of an attack - even though it may be factual, the adjectives are uncalled for. We have the opportunity to "clean" the post - removing the offending words - or delete it as an uncalled for rant. It does depend on the remainder of the post.