Yeah, doom is it's own animal for sure, and probably outside the realm of what I'm talking about. Though I would venture to guess that some of those soundmen you refer to just don't feel like arguing with you. A lot of the soundmen I've encountered would be like "Sure sure, I'll use your mic" then just mute your channel in FOH. Especially if they're house soundmen who run a lot of different bands, and aren't particularly down with the doom.
Used to happen a lot to ultra-loud metal bands back in the day. Every band had two guitarists playing through 100 watt tube stacks, ridiculously loud. If they were friendly with you, they'd tell you straight; "If you don't turn your stage volume down, I'm not putting you through the mains". And if they weren't, they wouldn't bother to tell you, and just mute you anyway.
Of course all bets are off if you are well known and can dictate special requests, or if it's your own soundman, or somebody that loves and understands the doom. But most soundmen just aren't that accommodating, in my experience.