I have created a thread about this over 3 months ago and it went without any reactions. Also it´s evident this request has gone unnoticed for devs as after the last update there is still no way to get rid of the annoying blue markers pointing the way. For a game that aspires for realism, I don´t understand it, as there is the minimap that can be followed. The "Show ingame mission markers" box only applies for freeroam mission spots, and not the scenario markers. Is there a workaround for this that can be done by fiddling with the files or is it more complicated than that?
Please be understanding, we are unable to monitor and notice every single post that happens across all our forums and socials. We are humans too. As for your original question, no, this is not a feature, there's no way to disable it, and at this moment there is no plans to make it disable-able (although personally I would like that feature too).
I appreciate your reply! Sincerely hope that it will be in the plans one day, though. I will return to being humble, now, that I know it´s seen by the people in control.