You shouldn’t read too much into the “tone” of his response. If he had given a less blunt response it wouldn’t have changed the fact that you most likely have mistaken what you had changed to get your desired result. And also, you did bump a seven year old post to relay a proposed solution to a problem that wasn’t relevant to the thread. This thread is about missing substation alpha support. Your issue is of subtitle selection/auto enabling which is entirely different.
As for your issue you have to understand a bit more about the details of your files and your settings. Subs have languages set, or not, and can have a default or forced flag attached. External subs might have this information attached to them with the file name, or not. There is a set of rules in Kodi that dictates if there is a matching sub and combined with your subtitle language settings it decides if and which are shown. To make understanding it worse there can be odd interactions with these various settings and there was some changes to the rules I believe not all that long ago as the behavior with forced subs in different languages wasn’t quite right. Additionally to all of this, Kodi will store if you manually change a subtitle track (which can confuse testing) but forced subs might override if you restart playback IIRC. In short, subs in Kodi can get quite complicated. There may be a simple solution however which may be just a matter of changing file_name.srt to file_name.eng.srt or file_name.eng.forced.srt. If you run across issues again please feel free to ask for help if you can’t figure it out. I would just ask that you do so in a new thread with sufficient details to help (debug logs and mediainfo).