Not necessarily true.
I agree with your scenario but I was referring strictly to internet based email addresses such as yahoo, gmail, hotmail, mail.com, etc. I believe this poster has an internet based email. I was informing him that there would be no problem accessing it from any internet connection. Even though Comcast and other ISP’s provide for internet access to your account, they are proprietary ISP’s and won’t provide continued access once you switch to another ISP.
Agreed.