Ok, Ok, Ok. I've been following this thread with a great deal of interest, as you might imagine - and as I see from the stats, so have an awful lot of other people.
I believe it is important in the first instance to remember just why people post their pens on the forum, and there are several reasons. A great deal of people simply like to show off their work to their peers - and there's nothing wrong with that. Often, those same folk don't necessarily contribute to discussions, and whilst it's always nice to see their work, its often difficult to build a relationship with them, therefore to critique or point out a defect is likely to cause offense. These people often post their work in many places on social media simultaneously and they are more than likely not here to be critiqued.
At the other end of the pole are those who may be near the beginning of their journey. They want to show their peers their achievements and their progress along the road, and they are justifiably proud of the pen they have made. Often those folk are their own harshest critics - they know they are beginners, and to wade in there with critique can be soul destroying for them. That is not to mention the vast number of people who visit regulatory but don't post their pens, for fear that they are not good enough, or for fear of being shot down in flames by what they perceive to be a small handful of people whom they can sometimes judge to be elitist.
There are all sorts of reasons in between those extremes, but if you try to remove from you minds, those regulars with whom you are buddies on line, with whom you have built a relationship, whom you know can tolerate a bit of banter and would take a quick jibe about a small defect in good spirit, ask yourselves how appropriate it is to find fault in a pen made by someone you don't know.
What I do not want to see happen is a system by which if critique is invited, people are pounced on, every little fault is pointed out and "helpful" suggestions for improvements are made, sometimes by keyboard warriors who have less or no more knowledge or skill than the maker posting the pen.
I see no harm in asking for critique if it's genuinely desired - a simple "C&C welcome" within the post would be all that is needed, but if anyone feels they have the right to point out a fault, and/or if C&C is welcomed, all l I ask is that it's done courteously, and in the same manner by which you yourself would like to be treated. As has previously been suggested, a comment in the form of a question can be a good approach - another gentle approach is to point out the good points first, then mention the defect you have spotted, perhaps finishing your comments with another good point. We all started pen turning somewhere, or in many cases are at or near the beginning of the journey right now, and even the most experienced of craftsmen and women make mistakes from time to time - so lets all be realistic about the comments we make, and polite with it. I agree that "nice pen, great finish mate" is not particularly helpful, and it can be quite dull to read a page full of comments like that, but if it IS a nice pen with a great finish, then why not say so. There is also the "Like" button for that very purpose if you don't want to physically comment.
For obvious reasons, I take issue with a foregoing suggestion that forums have had their day. You only have to look at the number of people that come here on a daily basis, the number of contributions that are made compared to other types of social media, the quality of discussions that are conducted here, or simply dip you toe in the vast resources of knowledge that exist within the archives to realise that is simply not true. If you want plenty of banality and "great pen, nice finish mate" then, yes I agree, there are other places that are better suited to your needs. But what is vital is that this forum to continues to lead the way in the future too, so please, let's all accept that everyone here has a right to an opinion, irrespective of experience or age, and let's take a grown up attitude to comments and critique, be honest about it, don't comment beyond your knowledge, be polite and courteous, and above all, enjoy being here.