If many people thinks something is true, is it true?

If many people thinks something is true, is it true? In my opinion, I feel that is it not true unless proven. It is most likely the media influence and false statistics that causes the public to change their mindset to be the same as what the company wants you to think.

For example, consumers uses petrol x for their own car instead of petrol y as the company of petrol x claims that their petrol is the most environmentally friendly petrol among the other petrols. After consumers saw this advertisement, they all felt that the company of petrol x is telling the truth and continues to pump their car with petrol x. However, is the claim that company x made true? Therefore, if many people thinks something is true, it is not necessarily true.

Although we do not have a viewpoint over a situation yet, we should not side with the crowd that have the most 'supporters' thinking that majority wins. We should try not to follow the crowd with their thinking as it will show that you lack critical thinking.

I am sure that everyone has their own unique viewpoints over certain situations as everyone have different ways of thinking and looking at a situation. However, people may have the same belief in a certain situation as they share same characteristics in their thinking or they do not bother to look beneath the surface. Take the very recent case for example, there is a man putting cats to sleep as he wanted to end their suffering. Animal activists and the public are against with what he is doing. However, are they doing so because a lot of people have taken their sides against the man? Yet if you think hard enough, could the man be right in his actions? Therefore, this is a realistic example that if many people thinks something is true, is still may not be necessarily true.