Teams are obviously collective interests, but they plainly compete, and of course it is this competition that gives interest to the spectacle. No one would pay for tickets to watch two teams walk on to the pitch, shake hands and agree to call it a draw (though this is the normal state of British politics). It would seem then that the attraction of such sports is to be explained not by collectivism in general, but by the special form that presents collective alliances in competition.
However, since we enjoy watching individuals in sporting competitions it seems safe to infer that competition in general is indeed very interesting to us, but then again there is a powerful tendency to represent single combat as a collective activity by regarding the individuals as representatives of larger collective teams, suggesting that we are significantly more interested in team sports than in competitive situtations involving individuals. That is to say, we do not project ourselves into a struggle between individuals by identifying with one of the two individuals, but by supporting a group of which one of the combatants is a member or at least a representative.
Thus, while it is clear that that competition in general is exciting to us, whereas collectivism in general is not, it is equally obvious that the limited form of collective alliances in competition is still more interesting than single combat. The implications for our evolutionary past are plain: inter-individual competition is real, but the interests of individuals frequently clashed through the medium of collective alliances and it is these latter situations that have moulded our psychological preferences.
Furthermore, competitive sports of all kinds seem to become more interesting to individuals in situations where real-world or economic competition is suppressed, by socialism for example or by the wealth preservation strategies of the elites (who castrate and remove the horns of their cattle, all the better to farm them). Unable to strive and better their lot in life, much of their energy is directed into the support of agents who are engaged in less restricted competition for advantage. In this economic environment individuals will enjoy the spectacle of single combat, especially in fictional situations or on film, but, as noted above, the struggle is often rendered collective in that the individual is held to be the representative of a collective interest, often nebulously the "good".
And of course, it is obvious that team sports, perhaps sports in general, are less interesting to individualists, who often enough betray themselves to their work colleagues by failing to take an interest in cup finals and test matches. In the UK enthusiasm for football overall and regardless of the team supported, is an important test of socialisation, and serves as an indicator that you are a placid member of the collective, venting competitive urges through this harmless medium.