@Ovinomancer,
@bert1001 fka bert1000
GM Force is neutral, in the sense that it's a technique - namely, the use of certain authority (over mechanics and/or adjudication and/or the fiction) in order to achieve outcomes and/or frame scenes without regard to the players' declared actions and the goals at which those declared actions aim.
Because of that
without regard clause (and the two of you have your own wordings, but I haven't seen anything huge at stake in that respect) it's perhaps a
necessarily suspect tool or technique, because we might have a default assumption that it's best to have regard to what the other game participants are doing in their play of the game.
Illusionism inherits that feature, and in a way doubles down by introducing also the element of concealment - concealment isn't per se suspect (we hide the presents we've bought from our loved ones, until we give them to them), but it lives in the same neighbourhood as
deceit which is closer to suspect per se.
I see
railroading as a label that is primarily pejorative because, rhetorically, it embraces and reinforces the negative judgement.
I see
participationism as a label that seeks to rescue Force and Illusionism from the suspicion they engender, by emphasising that the other game participants (i) are happy to be "deceived" (as in stage magic and at least some other theatre) and (ii) expect their contributions by way of declared actions and the aims of those actions to be manipulated behind the scenes to keep everything "on track".
There's at least a modest paradox in Participationism, because arguably the participationist players are ceding some of their authority to the GM, at which point the GM doing their thing is no longer Force because the players declared actions are not really game moves at all any more, but closer to
colour that the GM weaves into the overall sequence of events. (CoC play has a lot of this, I think.) My impression is that at least some D&D players look at D&D through this lens.
I don't think the paradox of Partcipationism is worth much angst. Whatever the best label, and whether we call it Force or call it a reallocation of authority among participants, it's pretty clear what the actual techniques are - and in particular, it's clear that player action declarations and their "surface-level" outcomes don't have the same standing that they do in other, non-participationist and non-Force based, RPGing.