Yes, Trump should be held responsible for the actions of his aides. They are, in fact, his aides, so anything bad that they do should lead back to Trump. Trump is, effectively, their boss, so he should be held responsible for their actions. People should expect nothing less than that.
Donald Trump should be held accountable for the action of his aides. He made the decision to hire the people, and should have properly vetted them. If a journalist was able to uncover a financial relationship between his campaign manager and Ukraine, Trump should have found it easily. He should be judged on the company he keeps.
Yes, Trump is ultimately responsible for the actions of his aides because he has employed them to represent his campaign. Trump should provide his aides with a mission, goals and a code of conduct to follow. Aides who work on his behalf are demonstrating actions that represent his values and beliefs, so he should be held accountable.
Every political candidate should be responsible for the actions of their aides, as they are employees. In the business world, higher-ups and owners are responsible for the actions of their employees. People at the top who wink and nod at bad behavior are responsible, whether or not they say or do the things themselves.