The historical background of Feng Shui makes it difficult to differentiate the true knowledge from false information. Having an open mind is important but unfortunately a lot of people misunderstand this term.
Having an open mind simply means to listen to various opinions. It does not mean to accept various opinions.
We respect others as human beings and respect their right to have their own opinions even if they are wrong but we do not have to respect the wrong opinions.
How do we know an opinion is wrong then? It can only be found out by sincere debates, by logical reasoning and by experiments. If people practise Feng Shui in a different way, as long as they are true to themselves, we should respect them as people. But if the theory is wrong, we do not have to respect the theory and it is our responsibility to persuade people what is right and what is wrong. If they do not have an open mind and will not listen, we have lost our respect for them because there is no sincerity towards seeking truth.
No one is right all the time. When people point out we might be wrong, we must listen but not on the defensive immediately. If it is a mistake, we admit it and correct it. If we are not wrong, we try to explain our position and happily enter into a constructive debate.