I've thought about such a thread, as well. On those occasions where I've ripped the latest eye-searing designs from modern automakers, or poo-poohed the Citroen DS, I've been taken to task by certain members of our site - one in particular who seems to thrive on attacking the opinions of others while offering little of his own - and have been chastened.
Each time I warm up to really lambasting an ugly ( IMO ) car, I'm reminded of this snippet from a movie monologue:
In many ways, the work of a critic is easy. We risk very little, yet enjoy a position over those who offer up their work and their selves to our judgment. We thrive on negative criticism, which is fun to write and to read. But the bitter truth we critics must face, is that in the grand scheme of things, the average piece of junk is probably more meaningful than our criticism designating it so.
But there are times when a critic truly risks something, and that is in the discovery and defense of the new. The world is often unkind to new talents, new creations. The new needs friends......"
Of course, Monsieur Ego goes on to wax eloquent about a culinary delight prepared by a rodent, but, I trust, you get the point.
So, let 'er rip. But hate the sin, not the sinner!