Simple philosophy: Changes to Wikipedia articles should always be justified.
You justify additions by adding a reference. You justify the removal of referenced material by explaining your reason on the talk page. Referenced material should not be deleted from Wikipedia without discussing and explaining it on the talk page.
Those who are changing Wikipedia on behalf of political parties or corporations can often be identified by the fact that they do not adequately justify their additions or deletions, blank sections without explanation, or resort to name-calling and incivility.