Some hotels purposely avoid giving out or having a generic email address. The reasoning is that too many guests attempt to use that email to make/change/cancel room reservations. Asynchronous communication is less than ideal when dealing with a product that is essentially perishable.

Note: I'm not endorsing this mindset. I'm also not looking to start a discussion on whether the use of generic emails is good/bad for hotels. I'm merely providing a reason why one hotel may have a public email while another will not.