...the Omniscient Narrator used "compliment" rather ironically here. Also, by far the most important thing at this point was to find Lydia, so Mr. Gardiner couldn't be too delicate! Remember, Darcy hadn't known what Wickham had been up to for years (except for his letter two years previously trying to get the living back, and then when he was trying to elope with Georgiana, at which time they didn't actually meet in person in the novel), although perhaps the Gardiners didn't know this. Also, remember that at this point, Darcy had not yet shown up on the Gardiner's doorstep, and the Gardiners really weren't sure what footing Elizabeth and Darcy were on, while they *knew* what footing Elizabeth and Wickham used to be on.