They force you to keep paying for a game which you want to play. When a miracle happens and a decent game shows up on IGC, you are forced to pay 5€/month for as long as you want to play the game.
Let's say that there is a good game which you haven't already bought on a steam sale on IGC once a year. In only 2 years, you have paid 120€ just to play those 2 games. In 3 years, it is 180€ and maybe 3 good games. If you are lucky.
You want that game go and buy it, from a store. Support the store and the developer. Don't pay for online gameplay on PS4 if you don't want it.
PS+ has never lied about it's stipulations and (before PS4) it was optional. You want to play the games, pay, you don't want to play them, don't pay. It's optional on PS4 but payment is needed for online gameplay. It's not forcing you to play the games. It's not hiding other services which you've already paid for behind it.
And what is IGC?