TexasCHLforum.com

I do not see how LIBEL applies. Unless what is posted is a lie and/or has the intent of harming the business of the instructor or the instructor personally, it is just the opinion of one person who has had direct interaction with that business. If I go to a store and am offended by the poor service or poor quality of the purchase, is it your contention that I should not say anything to other people who might also want to buy that product?
Is that just a convention of this forum? If so, why does it not apply to other subjects as well ?

I would agree. If it is a bad idea to mention an instructor that the reportee felt did a poor job, then it should by corollary be just as bad an idea to mention, gun shops, gun ranges, police departments, or anything else by direct reference.
Sounds like a silly idea overall to me. Most of us (I think) are smart enough to know that opinions expressed here are just that, opinions. Whether I THINK an instructor did a good job, omitted something important, lied to me etc is valid and important in allowing other forum members to collect information they need. Other students may have different OPINIONS. I would hope that they would also feel free to express them. Especially if they are contrary.
Bad experiences are subjective. Doesn't mean they are not valid. I would think that the forum would be the ideal place to post such information. In the interests of finding the GOOD experiences and flagging the BAD ones in any context that apply to our interests here.