Simjock, probably a company thing. In mine, we only respond to RAs, a TA only requires a good look out in response. There is no autopilot which will automatically respond to either a TA or RA.
And as for those who don't squawk when able - please do! Flying outside controlled airspace level a thousand feet below another aircraft in the airspace will only generate a TA (even Mode C against Mode S), which will prompt a better lookout in that sector.