I guess for anyone who sets out to deliberately misunderstand, anything's possible. For the rest of us the tilde clearly acts as a stand-in for the key phrase under discussion (in this instance 'spam').

*This is a local convention used in a semi-jocular shorthand for italicisation or other vocal emphasis. Every speech community accretes its own slang and customs. What can I say? - get over it. [/shrug]