What are some bad things Snowball does to harm Animal Farm?

Generally, Snowball appears to have the animals' best interests at heart and works hard to better the lives of all the animals. This desire is displayed in his indefatigable attempts at establishing various committees to educate the animals and ensure a better system for all. It is also reflected in his plans to build a windmill.

There are, however, some of his actions which can be deemed bad for the farm. Firstly, as a pig, he freely indulged in the privileges that the pigs claimed to the exclusion of the other animals. The milk and the windfall apples, for example, were to be equally divided according to the principles of Animalism. Snowball accepted these without protest. If he truly had all the animals' interests at heart, he would have objected against this obvious irregularity and demanded that the right thing be done. He did not. This neglect makes him equally guilty of creating an exclusive class. In this sense, he is just as conniving as Napoleon and his cronies.

The mystery of where the milk went to was soon cleared up. It was mixed every day into the pigs' mash. The early apples were now ripening, and the grass of the orchard was littered with windfalls. The animals had assumed as a matter of course that these would be shared out equally; one day, however, the order went forth that all the windfalls were to be collected and brought to the harness-room for the use of the pigs. At this some of the other animals murmured, but it was no use. All the pigs were in full agreement on this point, even Snowball and Napoleon. Squealer was sent to make the necessary explanations to the others.

Secondly, although it was decided that the pigs should perform mental labor and not perform any physical work, Snowball failed to also point out the unfairness of such an approach. He should have played an active role in the performance of physical tasks. Instead, he accepted the role of seniority as easily as the other pigs and supervised and managed. Once again, the principle of equality was ignored.

The pigs did not actually work, but directed and supervised the others. With their superior knowledge it was natural that they should assume the leadership.

Furthermore, Snowball allowed propaganda and deceit to flourish, especially during the early days after the Rebellion. When Squealer went around to spread his lies, which obviously were to the pigs' advantage, he did not intervene. He was, therefore, just as deceitful and manipulative as the other pigs. Clearly, even though things were unfair or unjust, he did not do anything as long as he could benefit. It is this reticence that makes Snowball as complicit in the abuse of the general animal population as any of the other pigs.

From the above it should be pertinently clear that Snowball played a role in ensuring that the pigs develop a stature and position of superiority and exclusive privilege. Since he benefited as much as the other pigs, he deliberately neglected to apply checks and balances to ensure that the maxim "All animals are equal" was adhered to.

Snowball's indifference, in this regard, created an environment in which the pigs' demands and needs came first and laid the foundation for the later abuse and exploitation of the other animals by their supposedly superior comrades. This, ultimately, is what ruined everything for the general animal populace.