If a guy does not care about styling or build quality they are OK.
They hit the sweet spot on price vs functionality at a time when the ML sport was popular.
Most folk can't handle it when others express their opinions strongly with conviction as you have here.
Two points I'd like to make.
In the early 1970s muzzleloaders saw an unprecedented rise in popularity because of the Bicentennial and a couple of now classic movies and TV shows.
TC had the vision to recognize an opportunity that no other US maker or manufacturer seized.
I contend that TC actually created a mass market that hadn't existed. Sure a few companies were flogging kits and subpar imports. But it was TC that fulfilled the demand (or did they create it) for Made in USA black powder rifles that were readily available, solid, worked, pleased the non-expert eye, and were easy to maintain. To top it off, TC rifles were backed by a warranty and customer service that to this day remains unsurpassed in the blackpowder shooting world.
To fairly evaluate TC sidelocks, I feel one should look at the company's impact and legacy.
TC introduced muzzleloading to more people in just a few years than at any time since smokeless powder and cartridge guns became the norm. I daresay the vast majority of members on this forum have fond memories of TC smokepoles. Thus, we are emotional about our TC sidelocks. From 1958 to 1965 I played with toy flintlocks like the one I saw Fess Parker carry on TV. In those tender years I roamed the woods of East Tennessee wearing a Davy Crocket **** hat, ever viligant for roving bands of bloodthirsty redskins (slaying them without mercy when discovered).
Imagine my awe just a few years later when I saw a TC Hawken in a gun store. I immediately spent the money meant for my meal plan at the University of Tennessee. Eventhough I was hungry all quarter, every weekend I was on the gun range at Norris, TN shooting ball after ball.
Finally, I agree with you that compared to other production sidelocks available from the early 1970s through the early 1990's, TC ruled.
Yes, TC flintlocks (that sold for less than $200) had serious issues, but one must ask what other company made rifles to satisfy the need for flintlocks in states that required them for deer hunting?
I would go so far as to say that if not for TC this forum might not exist.