Or they are what the local High Potentate is using to cow the masses . . .
Remember, quantity has a quality all its own. Sure that medium mech has a gauss rifle that does horrible damage to IndiMech . . . but it has a ton of ammo. So what happens when I send 2 or 3 lances of converted IndiMechs and a company of cheap armor (hello Scorpions!) out to get that mech?
If you cannot field a true battlemech but can field a converted IndiMech that has a AC/5 or LRM rack which is better- no mech at all or rough approximation of the same abilities under armed & armored? Some of the armed IndiMechs get quite capable but they are almost as situational as a UrbanMech. Also a low-resource unit like that is a lot more likely to end up in the militia's hands and the local militia's command SHOULD have a plan somewhere to impress IndiMechs to be armed.
No 'mech is better than an Indiemech under the Dirtbag Militia concept-the concept isn't to make the least effective militia you can, it's to use "Introtech" gear and builds to become a problem for top-shelf forces...and do so on a tight budget.
That industrialmech represents a sink of resources to arm and 'armor' it, that could be better spent on actually
effective elements like vehicles, ammunition, artillery or even infantry troops.
IOW it's not an asset. think "Finland in the Winter war". The Finns didn't waste huge amounts of money converting tractors into wannabe-tanks, they spent their very small budget and manpower on weapons and systems that were effective and could be effectively maintained and used in the field.
neither of which is true of an armed Indie mech.
remember, the dirtbag concept revolves around putting up one hell of a fight on a tight budget, not dressing up a farmall as an MBT that can't hold up against...light tanks. The direction to be looking, is the following:
1. You need to max out every C-bill. this tends to mean commonality of components to maximize every kilogram of storage/production/shipping space and every hour of troop training in your support arm. (aka going to a standardized model for powerplants or chargers so you only have to hire and train a single specialist to maintain them, choosing common calibers or similar weapons to maximize training time/outcome, etc.)
2. You don't have Helm Core Tech to help you out.
3. This means building to a tactical concept that uses a team concept balancing strengths to neutralize your weaknesses. (aka if you even HAVE 'mechs, they're a single type doing a specific role, other roles being covered by vehicles or infantry.)
an armed Industrial doesn't do that-it can't compete, so it's smarter not to try that route. Leave that to the morons from the Republic who don't have a functional grasp of long term survival or much in the way of practical experience, and the occasional Pirate who thinks being a ten meter tall target that is semi-immobile and poorly protected is just the thing to cow the peasants.
in simplest terms, "Dirtbag Militia" is about punching
above your weight, it's the planetary miliz giving the Jade Falcons a bloody nose, not the local Lord stroking his ego with the appearance of capability trying to mask a LACK of capability.