I had the Sam Adams Oktoberfest a week ago on draft. I had it after two other beers, so keep that in mind.
It did have a sweet finish, not cloying. I have no idea if it was to style. But, I didn’t think it was awful. It was easy to drink and I can understand why a portion of beer drinkers who like a sweet finish would like that beer. It may not have anything to do with Munich’s Oktoberfest but, people like the style, look forward to it each year, and buy the beer, so US brewers keep making it. Good or bad it’s now American Oktoberfest tradition.