" this is not an engagement ring " explain!

Besides if it's not appealing to you, what's wrong with this wrong for an engagement ring? Myself and my man are kind of clueless when it comes to things like this and he picked this ring for me. I liked it, until I started seeing things like this! People saying how ugly it is and how cheap men are if they get this. Calling it a cheap mall ring. Saying They would say no or take the ring back! My man spent almost 2000 on it. Can someone explain this to me?? I'm just curious, I still love my ring 😩