Cable channel numbers are a bit messy as there was no real standard, and they often go back decades. Comcast does have standardized numbering in the 1000's and are roughly categorized:
1000-1199: Local channels (numbers will vary from city to city), news, weather
1400-1599: General cable networks
1750-1899: Movies, premium networks
Numbers below 100 will vary from city to city as it dates back to the analog era when different towns may have had different providers. 101-999 will often be the same within regions as it came during the digital rollout in the early 2000's. (Example: in most of the Chicago area, WFLD-HD is 190, but WFLD-SD can be 3, 12, or possibly others.) Even 100-999 are often roughly categorized in many areas, but became a bit of a mess when networks changed formats over the years (FXX used to be some sports network.)
So why not just change them? People still tend to think of channels and networks by their numbers, and changing that can cause MAJOR outrage.
OK, I understand that, sort of. I had cable TV back when it was owned by Westinghouse (Group W Cable) in my area. The low number channels still make sense to me. But they should make the feature that automatically switches to the HD version go to the 1xxx HD channel instead of the 3-digit HD channel. It would be less confusing. The problem is that with the 3-digit SD/HD pairs don't match, paritally because they now refer to local channels by the network instead of the channel number, and I think partially because someone just didn't think. ABC is 3 in SD, it's over-the-air channel number, but it's HD counterpart is 231. That's why it's confusing when it auto-switches to HD.
BTW, in my area (south Alabama), the original cable company, Teleprompter, but OTA channel 3 on cable channel 2, OTA 5 on cable 4 and OTA 10 on cable 9 to reduce ghosting from signal leak-in. All of this was analog signals. Good times.