Yes, they have large, organized events there. Then, a large number of late events with no better place to put them are dumped there, as my events were last year, and others that I attended in prior years. I never suggested not checking out LOS, my point was that LOS events may have their locations assigned late.
I have a friend who has apparently developed anxiety and crowd issues (I say developed because we recently reconnected about a year ago and when I knew him when we were between the ages of 10 and 25 he did not have those kinds of issues, we are in our 30s now).
He went to GenCon for the first time last year and only went to the pathfinder hall and did not have any issues he told me of. In fact, he is planning on going again this year.
There are plenty of outer rooms and hotels for events and free gaming so you can stick to areas with less people (and videos, which are often less crowded).
Dealer hall does get busy. My girlfriend went for the first time last year (she also has issues with crowds) and she didn't have too many issues, and in fact insisted we go again this year when i was waffling due to not being able to get a downtown room.
If you decide you want to try and brave the dealer hall to look for something, I would recommend sometime on Thursday or later on Sunday. Those seem to be the less busy times.
And as I saw mentioned in my skimming of the topic, there is a quiet room on the second level of the convention hall to try and unwind in.
Speaking as someone who worked dealers hall, Thursday after 2pm was normally a bit less crazy, but still busy.
Sunday after the initial rush was chill. Noon onwards on Sunday especially.