If conditions are good and road is easily driven by RVs of course they should have pulled off on available pull outs, but if the available pullouts outs are unlevel, too short or consist of dirt or rutted terrain, no way would I pull over until there was something suitable. If a large RV is trying to make its way through mountainous roads and steep inclines pulling over will overly tax their rigs, particularly if after they pull back on the road they have to go uphill from a dead stop. Most drivers who have never owned a large RV just have no clue.
I know several truckers and they are hard working folk like most of us, but there are plenty who try to intimidate with their aggressive tactics, they have no problem pulling in front of cars and holding up traffic for many miles. No mention of which state, but they need to put more designated pullouts and passing lanes in these areas where big rigs, both commercial and private, can get where they need to go without holding others up. When I didn't know better I hated diesel commercial trucks and RVs with a passion, now as an RVer I understand the dynamics involved in controlling these large rigs.