I am not sure about bars, restaurants can have up to 25% capacity I believe but that is different than a church gathering for many reasons. I think it was linked just above but will share the link again here.
https://bgr.com/2020/09/20/coronavir...ovid-19-study/
We are talking about activities that are likely to create spread here, something like concerts and movie theaters and sporting events where large groups may be gathering together is a better comparison due to this. I would agree that a % with a maximum amount allowed may be better than just a total number (depending on size/distancing capabilities) but that isn't really specific to religion/church it would be an issue with the order placed in general. The restrictions on Churches fall in line with other activities closer suited to what happens there which will be different than other businesses without the same risk factors.
As was covered churches are placed in a category based on what they provide and the risk it poses. They are fighting to be treated like different things such as places that provide food or Nasty used school as an example (although a school in NY was moved to all remote with no one claiming its against the constitution).