I think I’ve raised this issue many times - but possibly on different forums.
The problem with such long posts is that they become super-sensitive to scroll bar movement. In other words, if you move the scroll bar by 0.00328 pixels, the page advances by about 247 posts. So, the only way to “scroll down” is by using the down arrow at the foot of the scroll bar to advance line-by-line.
Repeated use of Shift+Ctrl+End is probably faster than simply dragging the scroll bar slider.
I’ve made the point that the techie forums such as TenForums limit the replies-per-page to a specific number. So, you can jump immediately to a higher page number by clicking on the page count widget.
Here’s an example:
Amazon use a page-number widget, but they don’t allow you to jump too many pages, in case the advertisers complain about lost revenue.
If a page count widget is implemented on this forum, they should solicit some suggestions from the users first - because there are many good and bad types of page counters. The TenForums link that I posted above is nowhere near the best type.