The passive voice has legitimate uses. However, the active voice tends to be clearer, stronger, crisper, more colorful and generally better style.
The passive voice is widely overused as a way of playing it safe, obfuscating, and evading responsibility. Consider the famous circumlocution, "Mistakes were made." It's a way of avoiding saying who made the mistakes. Usually it's a way of avoiding saying "I made mistakes" or "I was responsible for the mistakes." The mistakes just happened, like bad weather, and we shouldn't hold anyone accountable for them.
The passive voice is used in "administrativese." It's used by people who want to sound pompous or formal.
In his famous essay, "Politics and the English Language," George Orwell says flatly:
"Never use the passive when you can use the active."
In "The Elements of Style," Strunk and White say "The active voice is usually more direct and vigorous than the passive." "The habitual use of the active voice... makes for forcible writing."