the 'incoming' transaction fee is just their way of paying the fee when you hand funds over to the recipient.
the pretend handing it to recipient is free. but thats because they deducted it when it was deposited.

any site you need to deposit to and then hand to a recipient and then they withdraw usually ends up as 3 transactions onchain.
just sites try to pretend the one in the middle is free by charging you more at the deposit or the withdrawal

its not really the services fault. onchain fee's are high so they have to play these 'deposit fee' games to then fund the 'swap for free' promotions because the swaps are not free if done onchain.

you will also find many exchanges pretend to have zero fee trading.. but then the spread (difference between buy and sell) is greater meaning you didnt technically pay a fee.. but it cost you more because the buy/sell prices are off