I don't believe that man can be strong and muscular without meat in his ration
No. It is possible. If you intake good quantities of protein, then your muscles will be strong and big. I agree that meat is a good source of protein. But there are other purely vegetarian sources as well, such as cheese, soya, yogurt, whey.etc.
True, you get all these other protein products, but absolutely non of them satisfies the tummy like a good chunk of meat. It's psychological in my case. I need to chew the flesh of an animal (non-human).