Beach Boys

I knew that the Beach Boys stole older songs, but not exactly how they stole the songs. In the film today, it showed that they stole the exact guitar part from Chuck Berry's Maybellene. I wonder how many of their guitar parts were stolen. I really enjoy the Beach Boys, but now it makes me wonder how original they actually were. I'm sure this happened with a ton of other aritsts as well. This isn't right. Also I don't understand how the Beach Boys could have had the crowd they drew if Chuck Berry was playing Maybellene on the radio and live. The American people should have realized this and seen that it was not right.