Political Ads and Undecided Voters

Mr. Mahe and Mr. Strother discuss campaign advertising. I thought it was interesting of Mr. Strother, who is a political consultant, to say that undecided voters sometimes decide last minute and that is why political campaigns usually run ads up to the last minute. He also says that this is because it takes people a long time to decide. He thinks that some voters “subconsciously” have somebody in mind who they want to vote for, but “consciously” they have not decided up until the last minute. This point confused me because I do not understand how you can subconsciously pick a candidate. He also said his consulting group will be running ads up until decision time.
This is interesting because it goes against what Garin's statements since
Garin said that at a certain point people stop listening to political campaign ads.
Mr. Strother’s remark sounds dangerous and irresponsible to me. I would prefer that voters have a candidate in mind and research them and their policies ahead of time. It seems a little irresponsible to me if people allow themselves to be influenced by ads.