Well... I have had 2 pregnancies where I have been in a higher BMI and not once did I have pre-eclampsia, high blood pressure or diabetes.
I am still above the BMI for this pregnancy AND I have been okayed for a home birth. My previous pregnancies & labours were considered for this and they saw that I have had great pregnancies and "labour like a champ" in their words.

Tell that Ob to check out how many women in the recommended BMI end up with PID, PE & high blood pressure.
I'd definitely be making a complaint too.
I hope the rest of your visits are much more pleasant hun