Public perceptions and the media narratives can influence betting odds in ongoing leagues significantly. The teams that are performing well, they usually will attract the media attention. This will in return, increase the betting volume of such matches. The media will usually set the trend and people will bet on the team that is more advertised by the media. This can be manipulated by the bookies as to how they set the odds for such teams.
You are correct and we gamblers without knowing will choose the teams that are getting over hyped by the media. The media has always being a problem because they do not get their facts correct but just do whatever they like. At times they are getting paid to do all the hyping of the players or clubs. When you keep on hearing about a particular team doing so well from the media, you will want to bet on them because you will think that they can not lose but when they play their next game, you will see them lose. The media that I know that are more guilty of this, is the English media, they hype their national team and their clubs too much that you will think they can win trophies when they are faces with other teams from a different league or country but yet they fall short of winning when they meet at finals.