Megan Fox is firing back at the people who are blasting her for sharing a GoFundMe for her friend’s cancer-stricken father … saying the haters don’t understand the full story or her relationship with the friend.

The actress took to social media Thursday to explain why she is helping crowdfund for her nail technician’s ailing father … instead of ponying up the money herself, as some folks online think she should.

Megan says her nail tech didn’t want her money because it would create an uncomfortable dynamic in their working relationship … and ditto for the woman’s other celeb clients.

In her IG story, Megan also questions her haters’ emotional intelligence … and ends by calling them psychos.

As we reported … after Megan shared the GoFundMe, donations started to pour in … but some folks questioned why Megan was asking other people for money instead of just covering all the medical expenses herself.

Megan also says she will oblige any request from her nail tech … though it will be done in private.