Rude and condescending. The pictures address a lot that is personal style and not level of formality. "See how comfortable and happy they are?" implies that, yes, "happy" guests (aka, desirable guests) will, indeed, wear Hawaiian shirts. Calling suits "stuffy" also implies a value judgement and not a positive one, either. I know plenty of gentlemen who do wear suits to wedding who would be offended to be called stuffy, even though they would be perfectly fine with being told "wear casual clothes and sandals", without the snide remark.