Red Indian Chief Torn Rubber said:
Because = is perfectly valid for a normal person.
= on its own in the language that most modern structural (includes OO) languages are derived from, which is C, uses a single = for assignment, not comparison of equality, == is used for comparison of equality. Certain modern languages add an extra thing which is === which means something slightly different.
In any case, unless it's a typo, a none coder would never put an == into a general comment for equality.