Are Light Frigates completely inferior to LRM Frigates?

Well, I'm not as experienced as most of the others on the forum, but it seems that LFs are useful in the very early game to expand to your first couple asteroids/deserts/terrans. Beyond that, I'm not so sure... I can imagine if you're super at Micro and you have the Sabotage Reactor researched you can use a squad of LFs to take out the antimatter of your enemy's capital ships.

Long Range Frigates totally own the basic attack frigates. You only make basic attack for some very early game military before you get long range, or late game to use their abilities to mess with support cruiser anti matter. Maybe to kill Flak if you don't have HC's yet. It has no other use.

It's not that they have no role, it's just that LRMS and Heavies can take them out so quickly, that you wonder why bother making them.

Sabatoge reactor is great for stopping Vasari and Advent fleets from using their supporting abilities. The problem is to do that, they have to survive my first point.

The only thing they're really useful for is taking out opposing supporting vessels, which have heavy armor, and flak, which also have heavy armor. They don't do too much to anything else.

Similar reactions here. Light frigs perform pretty well against non HC cruisers. Not just for their antimatter abilities, but damage wise. They can take carriers/cruisers down pretty fast, have decent hp, are resistant to strike craft.

The problem is that they are so heavily countered by LRM frigs. This dynamic is far more significant than that of LF against cruiser, and just about every player is going to be using LRMs as a backbone of their non-HC fleets. Light frigs are also more susceptible to AE capital ship abilities due to their size and required range.

Light frigs are strong against heavy armor, aka flak frigates and support cruisers. The problem is, LRF own them hard, and HC own them even harder and that's the majority of what people build. If any support cruisers get added to the fleet, they are always guarding LRF or HC and so the LF don't stand a chance.

So this leaves them with only a very small role, countering flaks. Considering most people don't mass flak there is usually no real reason to build many LF.

One counter to LRF spam is flak spam (at least to stall them, flak kills them slowly) so in theory combined LRF/LF spam may be better then straight LRF spam if your enemy is countering with flaks but I don't know how well that would work out in practice.

you can manualy send them around the enemy formation to land in their backs. they are fast enough.

so the cruisers and lrf have to shoot in the wrong direction to get them, which sucks considering you like to shoot expensive ships first and not turn around to kill some frigs...

In the start of the game LF help you expand but once you get better ships like heavies and LRF the only use i would use them for is to maybe send them in first to take some of the fire while long range and heavies take them out, there kinda an extra sheild. Other wise they take your money and time and are a 100% wasteful.

LRMs beat them in all ways except the sabotage reactor thing that messes with antimatter. They are still better than nothing like the old saying goes.  

Light frigates are good for decoys and targets for the AI's to kill while you focus on building actually GOOD ships

I find them a cheap filler for my fleet when I need to quickly increase the size of my armada to match an enemy attack. They aren't TERRIBLE, but do have their downsides. I'd rather have the LRM's firing at my LF's than anything else.