Maybe the reason why people don't see bingo (or lotteries) as forms of gambling is that the risk of addiction is perceived also as lower, compared to other games like poker or slots. We make the difference between soft and hard drugs, so I would say that we unconsciously make the same comparison when we think about different games.
You're right that one can also get addicted to bingo or lotteries, but at least it seems that it is not so common. It would be positive if we could see the real numbers.
I saw same people in my last apartment buildings filling several rows of lottery weekly, some playing even with same number, and they couldn't stop as if they would, they were afraid that those numbers woudl finally come, So they'll be playing those numbers their whole life as it's safe to assume that they will never come. Some of them also had a routine to buy scratch tickets on same days.
And one of my girlfriend was working in the bingo. She said that same faces were there constantly. It was a way to past the time and to see friends to them. So i would call that an addiction as they were using money for it the whole time they were in there.