Though the reception to Helldivers 2 has been generally very favourable, people started paying attention to all the different ways the game is monetised after most of the server issues were resolved and you could spend a few hours of uninterrupted fun.
The main point of contention appears to be the fact that the game’s Warbonds - effectively a battle pass of sorts, offers functional weapons and armour. These contain perks and passives that are not available elsewhere, meaning they are not cosmetic variants.
This has lead many to call it the system pay-to-win, a sentiment the game’s developer does not agree with.