Because, in fact, the status if the marriages, divorces, and conversions of thousands of Jews lay in their hands.
The problem is you can be a makel ,Machmir or chumra machmir. When dealing with Chilonim (and I mean non-religious people as opposed to anti-religious) you have to treat them differently. many Chilonim might very well up to a religious wedding, but it doesnt mean they want to go overboard. Charedi control of the wedding beraeu has caused approx 20% of Israelis to marry in Cyprus. Exactly what was accomplished by being machmir?
Being Machmir doesnt always get your desired results