I’ve never heard of aweber being referred to as a shady service before!
Aweber are an autoresponder service.Probably the foremost one available at the moment and currently being considered for takeover by Google. Autoresponders allow messages to be sent to you without the site owner having to address every subscriber individually.
If you don’t like it then don’t subscribe..after all by signing up you are asking to receive correspondence from the site owner.. How do you expect them to contact you with updates if you don’t subscribe?