In this weeks parasha, Pinchas, Tzlofachad's daughters go to Moshe and say about their father dying was not due to other people, rather due to himself. The gemara in Shabbos 96b notes that Rabbi Akiva says because he was the gatherer of sticks. Whereas, R' Shimon says he is part of the HaMafilim Shelach 14:4. But surely R' Shimon's opinion is saying that he was part of a people?
It says "he died by his own sin." The various groups were killed in the desert by plague or fire as punishment for their collective failure -- and to teach the rest of the people a lesson -- whereas the ma'apilim died on the battlefield. So it was his personal choice to gun a-blazing (okay, "swords a-blazing") into heavily-fortified enemy territory, and his death was a direct, non-miraculous, consequence of that. Apparently R' Shimon feels that qualifies as "he died by his own sin."