no, the statement would be, “I am not buying oil from a terrorist, and countries that we know are buying it from ISIS will be boycotted especially when oil is produced at great quantities here in the USA and Canada and we dont need ISIS oil anyways...”
The oil is still bought on the world market, the oil is still consumed. When a barrel or tanker of oil is bought and taken off the market, it impacts price and the oil will be replaced on the market. It does not matter if it is ISIS oil or Texas oil, it will be bought.
Even if you do boycott Iranian oil or Saudi Arabian oil, or ISIS oil, those entities will still sell their oil.