Snail mail is a public service, subsidized by public funds.
On the other hand, e-mail is a privately offered service, paid for entirely by private funds. The customer and service providers totally owns the email box and all email services. Email is based on a totally different economic and legal model than snail mail. A better comparison would be a private courier and document warehousing service. I don't think I would hire Mr. Mendolsohn to protect my property rights in a trespass case.