This was pretty much inevitable from literally day one where the wheels fell off of Brandon Webb. Scratched start turned into two weeks turned into a month turned into maybe All-Star break possibly.
I hate to see a manager fired this early in a season in any sport. But this is clearly a situation where the players had already given up on the season in April, and at some point the horrible defense, terrible situational hitting (and especially baserunning) and staggering number of strikeouts were going to come back to bite him in the ass.
Great guy personally and I hope he gets one more chance somewhere down the road, but this had to be done.
They surely ought to know what is OK and what isn't since they got a list of banned substances in the spring. The intelligent thing to do from there is not to take anything unless you're sure that it is OK.