Hovstad, like the Mayor, is easy to dislike. At first he seems like a good enough guy. He's a farmer's son who's pulled himself up by his bootstraps to become the editor of The People's Herald, the local newspaper. He claims to be true to his roots, and wants to use his position at the paper to further the cause of the lower classes. Even if you don't agree with his politics, in the beginning of the play he does seem like a straightforward guy who is true to his principles.
As the play progresses, we see that Hovstad isn't as straightforward as we might have thought. When he learns of Dr. Stockmann's discovery that the Baths are contaminated, his first instinct is to manipulate the situation to his advantage. Quickly we become suspicious that his support for the Doctor doesn't stem from truly believing that the people have a right to the truth. When he says things like, "When I took over the 'People's Messenger' my idea was to break up this ring of self-opinionated old fossils" (2.93), it becomes obvious that he just wants to further his own political agenda.
It's in Act 3 that Hovstad reveals his true colors. First, he makes a pass at Petra, Dr. Stockmann's daughter, and alludes that one of the only reasons he's supporting her father is to get on Petra's good side. Then the Mayor shows up and easily turns Hovstad against the Doctor. The Mayor reveals to Hovstad that in order to make the necessary renovations to the Baths, they'll have to raise taxes in the town, and that it will most likely cause everybody financial ruin. Hovstad knows that his newspaper's readers will hate raising taxes, and that if he supports the Doctor The People's Herald will go under. The decision to betray Dr. Stockmann seems to come pretty easily for Hovstad.
All in all, Hovstad appears to be Ibsen's representative of the liberal media of which the playwright had a pretty low opinion. In a letter to a critic Ibsen wrote, "What are we to say of the attitude taken up by the so-called Liberal press – by those leaders who speak and write about freedom of action and thought, and at the same time make themselves the slaves of the supposed opinions of their subscribers?" (source). This is exactly what Hovstad does in An Enemy of the People. Though he claims to be true to his ideals, he feels it necessary to compromise what he prints based on public opinion.