Yep That popup is pure marketing group . They are a law unto themselves. That said the tactic must work to drive renewals otherwise they would not use it.
Probably but it is still a pain to have to close pop-ups constantly. Like I said before I would understand the ads if it was 'freeware' but if you pay for the subscription you should be able to turn it off. The only other option would be to use another antivirus and besides this I have been very happy with McAfee over the years.