Hard knock life

Today I was chaperoning when Kate's school went on a theater field-trip. It was a normal trip, some hyper-activity due to excitement or boredom, some arguments, some laughter and an OK production of a children's story I had never heard of before.
On our way out, there were the usual scrum for the stairs and I got caught behind a little boy around 4 years old who was trying to slide down by holding on to the rails. I didn't pay much attention 'cos I was busy not loosing sight of the kids when the mother urges to boy to step out of the way and then turns to me, very flustered and apologetic:
- I am so sorry. He's A-U-T-I-S-T-I-C.

I was very taken back by this. Not only did the boy display what I find is normal, healthy, physical boy-behavior. There was absolutely no need for the mother to apologise, and defiantly no need to use her child's condition as excuse. I didn't even think twice about what he was doing, after all, every single boy and half of the girls in Kate's class had been sliding down the same rails 30 seconds earlier.

I felt really bad. Is this what us parent's do to each other? Do we make each other feel so inadequate that we feel the need to constantly define our children openly in order to have them and their traits "explained and excused"? Imagine me trying to cover up the rambunctious behavior of a school class of 19 trying to keep quiet during a theatre performance:
- I am so sorry. They are E-I-G-H-T Y-E-A-R O-L-D-S.