The thing about a concept like "Heroes vrs Villains" is that at some point almost every team does something that might be considered under handed. From trying to get another's cab, to blocking or cutting in line, to lying, to breaking your word, to misleading other teams, to trying to enlist locals to hamper other teams (surprisingly this has actually happened), ect
But so much of what we see is very subjective and can be enhanced by editing.
Then we are put in the position of do we think a team is a villain do to their attitude or should we limit it to just their actions.
Take Rob & Amber, Rob's actions as a racer (like bribing a driver to let them out first and not release the other sections door was a crappy move and one several racers agreed with including Uchenna & Joyce as was taking another teams cab), but personally his attitude towards the other racers made him a villain in my book, more then his racing. Just as Lynn & Alex (from the same season) humor, often went to a fairly negative place.
For others it might be more how they treat each other or how teams treat locals that might put them in some people's lists for Villain.
And of course all of these things are subjective.
Take Charla & Mirna and Ron & Christina. Both have large groups that love or hate them. While I loved seeing Charla (and Mirna) have to overcome the disadvantage that Charla's height puts on their team, I found how they interacted with each other, with some locals and with other racers to often be utterly vile.
Ron & Christina have fans that loved to see Ron change in how he treated his daughter over the course of the season (which I did as well), but the fact that in the episodes, and in the clips we see him in 8 out of 11 episodes) be mean or rude to either his daughter, locals, fellow racers and even race personnel utterly appalling. But many completely disagree with me.