Welcome to Moodle.org Andrew.
You have understood the situation correctly, and Mary is right. Welcome to the Moodle "Scroll of death". Something at the moment we just need to work around. [search for "Moodle scroll of death"]
When you land at a course in 'single section view', you get the titles of all the sections in one page - click on the title THEN you get the one section view.
This is better than in the old days where you ONLY saw every section AND contents.
Once you get a greater number of sections in Moodle, navigation is difficult, at least that is what I find and my students tell me. You will find this question talked about here in the forums back to dot. Some of the posts are from me. Most Moodle Partners have a solution, and some of these are in the plugins database. As well as some others.
Possible solutions:
Course menu plugin: my current pick
At present I use the course menu plugin to help. https://moodle.org/plugins/view/block_course_menu
See the illustration here: https://moodle.org/mod/forum/discuss.php?d=316278 This was my latest attempt to work on this what I see as a problem, but at present, no traction.
Even with 26 sections, the navigation is not too bad. Especially with subsections in the menu. Still a hefty scroll if you read it all, but you can get a nice compact menu to start from, and often one or two clicks and no scroll to get their.
If you like voting on issues, my tracker item from 2011 is here: https://tracker.moodle.org/browse/MDL-27039
One topic plugin
If you have only a few sections, ONE TOPIC does what you want. Opens at section 1 automatically.
https://moodle.org/plugins/view/format_onetopic
Not so good for many sections. But I have dot it going well using Topic 1-Topic 20 with a description for each one. There are other tabbed options.
Coding
Spend hours coding a page to link to the sections. eg https://moodle.org/mod/forum/discuss.php?d=153776#p673006
I heard someone had 'solved the problem" and traveled to visit them. This was their solution. Individual coding the links to each section.
Other solutions
Let me know if you want more ideas.
Good luck.
-Derek