I think there's a little bit of dismissal on both sides here, because people want very clear narratives about what happened. Some people feel good saying, "Trump won because people wanted him." Some people feel good saying, "Trump won because the system was hacked."
Both of those claims are simple. Either the election was a farce, or nothing is wrong and all the criticism is fearmongering. That kind of simplicity feels good.
It doesn't feel as good to say, "Trump won in part because the system was hacked, but if a bunch of people hadn't also genuinely wanted him, hacking the system would not have been enough to make him win."
People are hardwired to look for clear, easy-to-reason-about patterns or rules that they can just universally apply to every situation. Real patterns like that are rare, usually uncommon events have multiple causes. Usually reality is more complicated than we expect.
I don't think that bots/plants are as big of an issue as people say. I certainly don't think they're an existential threat to democracy. I also don't think we should ignore them, I do think they have an impact. They're one element of many that can influence an election.