weight guidelines and charts

So, I am wondering about weight guidelines and what WW says we should
weigh. According to everything I have found they say I should weigh
170-175 pounds. There is no way i am going to weigh that little
withoout losing serious muscle mass.
is there anyone else here that finds that goal a little unreal? My
goal weight is 240 and I will adjust from there. Even then I would be
considered obese by government weight charts.
My DW has heard me rant about this from time to time and just looks at
me and nods her head. I think she is thinking, just lose the weight
and see how far you can go.