This is last time I'm bothering respoding to you.
Difference of between mainline infantry squads and elite squads are their weapons upgrades along with baseline performance. Penals perform equal to riflemen on single model basis. They also lack proper weapon upgrades and scale similary to other mainline infantries of other factions. This does not make them elite squad, merely more equal to compared to their peers in comparison to Conscripts.
PanzerGrens have huge received accuracy bonuses and their default weaponry is far better than those of baseline infatries, they also have powerful weapon upgrade options and scale better into late game.
If you want to continue this you have to argue it with Relic and creators of the guides of this site.
From Soviet units guide which is updated recently and included the change to Penals in price abilities and weapon upgrades:
{Penal Battalion
"
Elite anti-infantry squad."Can be upgraded with a Flamethrower and can throw a satchel charge for high area damage.
Production/reinforce cost: 300/25 manpower
Population cap: 8
Abilities:
Throw Satchel Charge - 45 munitions; Can be used on vehicles to cause engine damage
Targeted Satchel Charge - 45 munitions; Can target enemy vehicles (exlusively) to deal heavy damage
To the Last Man - passive, Increases weapon accuracy, rate of fire and improves survivability when the squad loses members.
Upgrades:
PTRS 41 Anti-tank rifles - 60 munitions, grants 2 PTRS 41 AT rifles to the Penal squad
Tips: Penal Battalions carry much more powerful rifles than conscript Mosin-Nagant rifles. Penal battalion's satchel charges are excellent for destroying emplacements, decrewed heavy weapons (such as Pak 40s), and immobilized vehicles. Can be used on incoming vehicles to cause engine damage. The PTRS 41 AT rifles upgrade nerfs the Penals anti-infantry capabilities severly, use it only as a last ditch effort against the light vehicles. }
https://www.coh2.org/guides/2574/soviet-unit-guide
(edited to include full text for penal in guide)