It’s a hoax. There is zero point zero diminished safety. It is possible there may be some delays, but no compromise in safety.
Edited to explain...
There are two major entities affected, Air Traffic Control (ATC) and TSA.
Granted, neither wants to work without a paycheck, but ATC still isn’t going to vector (turn) two airplanes so they will collide. It IS possible that some may call sick which would reduce the volume of traffic that can be handled.
TSA, unlike ATC which is truly a well paid career job, works on a different level. They do not make the money to handle multiple missed paychecks (although they will get paid eventually).
They may call in sick or resign in record numbers which may slow things down. But, I HIGHLY doubt any working TSA professional will purposely let a gun go through the checkpoint.
Again, it may slow it down, but in my opinion will not compromise safety.
Source: Professional Airline Captain
Open for questions...