Why doesn't yahoo have secure email like google https.//gmail.com ?

Because they're Yahoo! and they're lame. You actually do have the ability to log in that way by putting the "s" on the end of "http", however, unlike Gmail, it is only for the login. With Gmail it stays secure the whole time you're in it, regardless as to whether you're in your inbox, sent mail, or reading, composing or sending an email. Much safer when you're on a public WiFi network.
Why doesn't yahoo have secure email like google https.//gmail.com ?
They do.