Just as you think your dd's, and your family's comfort is a valid reason why a 7 year old boy shouldn't be in there, another familiy's comfort is a valid reason why they think they should.
The one thing that bothers me the most about the DIS, is that some people think that IF my child can do it so can yours. And I hate to break it to people that kids are humans not robots. Kids will vary in maturity levels even at that MAGICAL age of 7. In a room full of 7 years olds, you will have every level of maturity happening amongst the boys and the girls but usually boys fall on the lower end of maturity. So you will find kids who are quite capable of sitting on a bench and there will will kids who cant handle that whether it is anxiety or maybe ADHD. You will have kids who can handle the independence of going into the men's room, whether it is hygiene or zipping up pants, or dealing with a stranger.
There are many people who think since my kid can ride his bike to school by himself that everyone should have that level of independence, not every neighborhood is set up for that.
I have two boys who are as different as night and day. I thought I was the perfect parent with DS13 bc he was so independent, so confident, so smart etc. Then I had DS8 and he had many physical delays that made dresssing a challenge, it still is but he has improved greatly but he is not on par with all of his classmates. Most people have no clue looking at him. He is also my anxious kid, quite a shock after having DS13. He is a very well behaved 8 year old so he would stay on that bench but the anxiety he would feel would be detrimental to all that we have worked towards. Will he get there eventually, yes, but I am not about to have his progress derailed bc of some other parents who think that he should be doing A, B and C by age 8.
And for the record, he rarely goes into the bathroom with me anymore, we started the process last year, and even when he does(very rare) or did, he went in the stall with me.
Last year, we had a black pickup truck cruising around the middle schools, trying to lure kids into his truck. All schools were made aware and all parents notified. I took this time to go over DS8 (7 at the time) what to do, I thought he knew since I have been drilling it into him, yet he seemed clueless, so we went over it AGAIN.
Then that weekend at flag football, standing on the sidelines with a bunch of other 7 year old moms and dads, we discussed the maturity level of our kids. They were all over the board. One interesting observation I made was by a no nonsense mom who had an DD12, and twins girl DD7 and a boy DS7. She said that both of her girls would know exactly what to do, but her son, who was one of the most popular kids in the school, she said had not an ounce of common sense, and would probably take off with anyone who said cmon I will toss a football with you. I just found it interesting bc she is very about having independent kids but she knew that her son was not at the same level as her DDs.