Why are Pro Range routes and locos being released in this game when the game is called Trainsimulator classic? Classic should mean that you play it in classic style and not in advanced style. Or should should be able to choose between Pro och Classic playing style. You should not be forced to play it in advanced style.
It was changed to Classic to avoid the name changes on a yearly basis for the longest time, not to mention it is to show it is the older DTG train sim compared to Train Sim World, since some people got lost and posted TSW stuff on this side of the forum.
A couple points as well, Pro Range as a label doesn't really mean anything, the DTM P40 was somehow labeled as pro range for pete's sake. Secondly, pretty much any addon with genuinely complex features will state as much both in the manual and on the steam store page, it's not like you bought something expecting a slot car and were surprised when it turned out to be the Searchlight AC44. Obviously different people want different things from the game, but if you really want less complex simulation, there's lots of TS1 content that fits the bill, as well as almost everything in TSW and literally everything in Trainz should you so desire.
Words can have multiple definitions/meanings. In the case of TSC, the "Classic" refers to being the old-format game (scenarios only, no timetable) compared to the newer Train Sim World (where you can walk around on foot, run timetables etc). Think of it as Apple keeping a previous version of the iPhone still in production, with the "old" format (smaller screen, thicker housing etc) but still having base/Plus/Pro/Max performance spec levels available, alongside the current "new" format (larger screen, more "bells and whistles", better graphics but not necessarily better as a phone)
Pro range DLC has been around for some time before Train Simulator changed its suffix to Classic The Pro Range usually refers to Locomotives that need more than the normal brakes off, apply power mode that fits most DLC. And its for people like yourself who don't wish to play advanced locos that they have the Pro definition. If you bothered to look at a Pro Range DLC you would get more info on what is required. Pro Range The Pro Range is aimed toward the serious train simulation enthusiast looking for a complex machine to master. Each product is designed to provide education and entertainment for users. Xbox controller and HUD interface support do not come as standard and users will need to read the accompanying documentation to fully understand the operation of this advanced simulation. If you bought Pro Range DLC because you did not read the information then its your fault.
As said above Pro Range is the how realistic and complex the locomotives, the manuals will normally go through these and how to get them moving etc if you get stuck.
I think you're mixing up casual and classic. Casual also has two variants, one is easy-going while the other is low-frequency. Either way, low-effort.