Generally, security rules are made and enforced by USA authorities. Any airport which doesn't fly to the USA only needs to follow local rules of the country they are in, which while typically are as strict as the USA rules, are typically not enforced.
Some airports for example only xray one in 10 bags at peak times, or none at all if the machines broken.
Source: Personal experience only, but I've been to a lot of airports.
Hartsfield International does this regularly in Atlanta when lines backup too much. They'll open additional security lines, divert people into the Special Needs and TSA Pre-Check lines, a shut off the nudy scanners (backscatter x-ray) and just run everyone through the metal detectors as fast as possible.
US airport security is not separated between international and domestic flights. I don't know what the parent poster meant but it can't be that, at least not for US airports.
Which airports? US domestic flights? Because internationally I've never seen this happen.