Politics (unlike the workplace in general) is one area where I concede the declining clothing standards actually indicates real trouble. While in the workplace people should be left alone to wear what's comfortable, politics is a public business, that needs to meet the standards of rational democratic discourse, with the attendant rationality, sober attention to detail, evidence, and viewpoints, decorum, consideration, manners, etc. Some form of appropriate, calibrated dress seems virtually an imperative to match a real, thoughtful, solemn, debate.
Obviously, none of the above applies to the orchestrated freakshow that passes for democracy (LOL) these days, so the decline in dress (getting sloppier, pimpier, or both) is simply a lagging acknowledgement that the whole thing is a charade. Heck, I'd imagine it is far easier to spout inane bullshit and lies in sloppy garb than it would be in some sort of dignified attire.