[Antinome]

I think you're off-base.

Random uNL players do not steal from the SB, their raising range is barely wider than a button raise. You're ahead of that range by a little bit, and in position. I flat call here the way I might flat call AK on the button- for deception, to keep the pot small. Let him make a bigger post-flop mistake with whatever crappy hand he has instead of a marginally bad preflop call.