TFB is TUNED for Camapign, people don't have the option of overgearing it without spending a fortune. HM EC is tuned for un-augmented Rakata, but most people can't clear it in that. Anyone that can, should be able to clear HM LI in Tionese/Columi mix.
Most of the people can at least do a few bosses and get upgrade from it. As for Tionese groups, I've yet to see one not wipe on that mini boss at least once and not died horribly against LR-5. The 3 bosses are around the same difficulty, all of them are not friendly to Tionese. LR-5 is a challenge to the whole team since there are a lot of things going on during the fight and melee DPS need to move well. Sav-Rak is mostly about healing. Lorrick is tank's position skill and a challenge to DPS.
HM EV/KP are also TUNED for Columi. Doesn't mean the majority can do it in those, but those groups that do head in there with Columi will get upgrades.
Yes they can, at least quite a few bosses.
You're now comparing what something is TUNED for with what most people can CLEAR it in. Yes, it is possible to clear content in the gear it is tuned for, that is the point! It is possible to clear LI HM in Tionese, which it is tuned for. Just because some people can't, doesn't mean it is wrong.
But the majority, again, need Columi to clear it, especially people who never did this FP before
And it's not like the ops, you can clear a few bosses, which are significantly easier than the final one and try next time with better gear. LR-5 is not easier(not much) than Lorrick to Tionese groups.