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JavaScript ES6, 50 bytes, 67.95%
Correctly identifies 585 starred and 774 non-starred.
x=>/^<|t[ao]r|l.x|bot|pin|ol|[;ÿ-ff]|<.>/i.test(x)
Returns true if the message starts with < or contains any of star, bot, pin, ping, alex, italic text, bold text, a link, a semicolon, a non-ASCII char, or...