Muting a player should not mute pings. In this case, yes it would be helpful and reduce your exposure to toxicity. However, if you mute someone (let's just say they are a racist redneck) muting their pings can make normal gameplay difficult if not impossible to coordinate. How do you know when they need help? What if they see the enemy jungler coming to your lane and you didn't? What if they are coming in for a gank and you are tunnel visioned on cs?
Perhaps rather than muting pings, muting a player should reduce the number of pings that are issued when spammed. So rather than the five or six limit before it cuts off a players ability to spam, it would only show one or two pings. That way the muted player could still ping caution to indicate an incoming gank followed by I'm on my way to indicate they are counter ganking.