The law permits reasonable airport security searches. These must be effective, consistent, brief, and must not be targeted at general law enforcement. For example, TSA searches for the purpose of finding drugs are unlawful. (If TSA happens to find drugs during an otherwise lawful search, that is another thing. But there is ample evidence in various threads on this site, and elsewhere, to believe that TSA is looking for drugs -- whoops!)

No court has yet given an opinion as to whether the current regime is lawful. Where however the search is not supported by a warrant issued by a magistrate, the burden of proof rests upon the government to establish that the search is reasonable, and if it is not, it is unlawful. So, right now, the legal presumption is that TSA's current search regime is unlawful.

And even if in theory the TSA regime could be lawful in general, in particular there will be very great difficulties in carrying it out in a lawful fashion.

For example, the glove issue. It has yet to be shown that there is any connection between failure to change gloves and enhanced security on the aircraft. I would say that where TSA's default state of hygiene is never changing gloves unless they are requested, the courts will not sustain this.

And certainly, if a TSA agent were to carry out an intrusive search of the passenger without changing gloves, and doing so in a proper manner, that search would be unlawful, and possibly criminal.

I need hardly add that the bursting of ostomy bags, yelling out "Here's another cutie" and so forth will cause a search to be regarded as unlawful by the courts as unreasonable and unnecessary humiliation.