Partner visa fees etc

Hi I am a newly joined member. Due to the high fees for partner visa (122% increase over last two years?) this must be considered usury, imaging if the banks increased their fees like this. Is the govt or immi trying to subsidise the recent cost of illegal or sirian intake costs by penalising people who apply legally and genuinely want to come to Australia to be with their partner>? How can they justify this increase.? The same fee applies for a rich countries as to the poorer countries. And its not means tested? And you cant pay it over the 6-12 months by instalment?
My example: My partner is here on a visitor visa, and now on bridging visa waiting to extend the visitor visa ( I want our baby born here in Aussie) costing $350 compared to the cost of nearly $7000 to apply onshore for a partner visa which would be more approapriate but she cannot as simply cant afford to do it. Its not fair. Not sure how to approach this to the department minister, Any suggestions?