" A given poll or pollster may have an agenda but that does not translate to a systemic conspiracy. Gallup is a respected polling organization. Most of their polling predictions fall within 3% or so of final outcomes, many times less. "
while a conspiracy doesn't exist, how polls are presented are often one of the most politicized and biased element in public discourse.
there are also numerous biases against telling a pollster you have a weapon.
In this day and age of phishing you don't really know who is calling. It could be a burgler. After all the value of weapons just went up about 20%.
In this day and age of hacking and hactivism you are not in the least bit paranoid to think that data you give will be secure over a period of time.
Also lots of people would consider that private generally and answer negatively even if they have a legal weapon. After safety and use instructions my father hammered to me that you never tell anyone their are weapons in the home. Now he hammered that not out of a fear of the government, but out of concern for burglary, and probably when I was a teenager for my friends knowing. His weapons lessons are so firm in my mind that it remains second nature for that reason for me to say no, if anyone asks me.
Lastly lots so people will answer negatively due to social pressure. We know in the past there that there is a weird but consistent 2 to 5% evaporation for african American candidates between polling and voting. Some hypothesize that some amount of that was respondents concerned they would be though of as racists by the pollster on the other end of the phone.
So if some portion of owners feel some shame or feel they will be seen as outside the norms, even to an over the phone poll taker, they may report no weapon due to some stickiness for some portion of the population in the clear campaign of social shame that has been deployed as a tactic by the anti gunners.