To be clear, here's is Uphaw's timeline:
He went to Fresno State out of high school. He was suspended twice and then kicked off the team, all in his first year. He said that was for drugs, although I don't believe the school said so one way or the other. He was also the highest-rated recruit in Fresno State history, so to get kicked out of school in your first year takes some effort.
He transferred to Washington. He had to sit out a year of playing due to NCAA rules, but could practice. However, halfway through the season the coaches banished him from team activities.
As a junior, he played well and said the right things until being suddenly dismissed in late January, for "violation of team rules", which could or could not be drugs. I can't link it on my phone, but I found the Washington athletic department drugs testing policy. You get four positive tests before you're kicked out, assuming you follow the rules after the first three, which include things like meeting with parents/guardians, counseling, etc. No mandatory suspension is called for, but one can be given at the coach/AD discretion.
Anyway, if Upshaw were kicked out of UW for drugs, that means he either tested positive four times in 18 months, or refused to follow the pretty lenient requirements after tests 1-3. This would be on top of getting kicked out of Fresno State for drugs (allegedly), after presumably at least three positive tests in about 8 months (assuming that his first two suspensions were for drugs, and he was suspended immediately after the first test).
If it wasn't for drugs, then he was such a jerk he got suspended/kicked off his team three years in a row for other behavioral issues. In either case (7+ positive tests for drugs in under three years, or being such a locker room cancer to get kicked out), it really is tough to chalk it up to one or two mistakes, and really does look like a long-term pattern of behavior.