I'm not certain your statement is accurate. The TSA has itself demonstrated, time and time again, that their accuracy and precision leave much to be desired. If anything, they've been lucky. Terrorism, thankfully, is quite rare.
If anything, I hope the shutdown helps push airports and airlines to seek control of their infrastructure (and, with luck, this administration will help diminish the power of the executive branch in the future).
I wouldn't say we should get rid of police or that they don't provide a service because of those issues...just that they need to reform/change/fix those issues. Not sure, how they do that...
My point is the TSA, while it often does some shitty/shady stuff in the name of 'security'... I don't think you could say they have never thwarted terrorist attacks, or that we as a nation could flourish without them at all.
I don't really have statistics on TSA/etc... but I think making sure people don't have guns on planes is a bit more important than building a wall that can be scaled via ladder, or tunneled under. But it's just ironic to me that by not getting his wall, the TSA is now basically on strike.