Euro-zone banks concentrate all the risk aversion: Why?

Each time an event (tariffs imposed by the United States, bad news about the growth outlook) leads to an increase in risk aversion, euro-zone banks’ share prices fall much more sharply than economywide equity market indices in the euro zone or other regions. Why are euro-zone banks so highly sensitive to investor risk aversion? Because euro-zone banks are fragile (low returns and profitability)? Because bank shares are a useful hedge against risk for investors (shorting bank shares provides a hedge against risk)? Because robots have figured out and are perpetuating the high beta of bank shares?