because he taught and studied to his associates that when you combine a dominant trait with a less dominant or more passive trait you get more offspring ( doesnt matter really) with the dominant trait ... for example brown hair and brown eyes is more dominant then blonde hair and blue eyes or green or blue eyes etc or with certain products like the pea experiment where some came out lighter then the others and it was a direct problem for him because he knew that it would be harder finding the dominant trait this way
The principle that recessive genes will always be masked by dominant genes is Mendel's principle of Dominance. Alleles are different forms of genes and they can be dominant or recessive. According to Mendel's principle of dominance, dominant alleles mask the effects of recessive alleles.
