Taking clenbuterol as an endurance athlete just doesn't make sense. Yes it does help increase lean muscle mass, specifically fast twitch muscle fibers, and decrease fat mass, but it has many negative effects that would outweigh its benefits for endurance athletes. Studies have shown that the use of clenbuterol decreases cardiorespiratory fitness, which causes its user to be unable to maintain their normal level of intensity during workouts/competition. The drug also causes cardiomyopathy, or enlarged hearts, through fiberous connective tissue and collagen, not muscle. It decreases cardiac output and increases the risk of cardiac arrhythmias. It can also lead to cardiac cell (myocardium) degeneration. Other side effects include muscle cramp and hypertension. World tour cyclists should not have an issue reaching ideal race weight, lean mass/fat mass ratio, or strength given all their "legal" resources.
Basically, a team doctor, athlete doctor, or whatever you want to call him/her with any background in pharmacology would have to be an idiot to prescribe clenbuterol to a professional cyclist.
That's long-term usage. Short term usage doesn't have the same sides in many and it doesn't inhibit performance in many. A lot of MMA fighters and athletes at my old gym used to use clen for a few weeks before competition to help make weight. In the right dosage its not a stark difference and in a sport where 1-2kg matters, decreased performance (slightly) in a race you don't care about might be worth it. Its not like he was Schleck bad in the race or even Froome good to start with so it becomes a wash.
I agree that they shouldn't have to use it, but there are a hell of a lot of things they shouldn't have to do that many do.
Don't take me too seriously. GramzStrava