Everyone know what is meant by “the grass is green”, some people just have to be disagreeable.

The grass is blue in Kentucky.

the good stuff usually is.

The grass is greener over the septic tank is a metaphor for that it, often takes a lot more hard work to achieve other people's observations than other people will ever realize. In essence, it takes sewage to makes things look beautiful.

The grass is 'mainly' green. Or the grass is 'generally' green.

You raise a good point. Since it is a good idea in debate, especially where your opposite is likely to use such low devices such as straw man arguments, to anticipate that, and straw-man or at least qualify yourself first when you make a statement. That way you both steal their thunder and block the straw-man argument. And if they still press on with it, you can point out that they are at the very least inattentive, and that you already covered that.