FUD.

They've done this fueling 30+ times now and understand the risks very well. The issue that caused the explosion on the pad in 2016 has been corrected. The engine issue was only discovered because they can examine an engine after use. And multiple people have shown that the Dragon's ejection system would have been more than enough to get a crew away from the pad in the event of another Amos-6 style fueling mishap.

This article first popped up on the Washington Post which has a few people angry as the Post is owned by the main competition to SpaceX.

The concerns from some at Nasa are shared by others. John Mulholland, who oversees Boeing’s contract to fly astronauts to the International Space Station and once worked on the space shuttle, said load-and-go fuelling was rejected by Nasa in the past because “we never could get comfortable with the safety risks that you would take with that approach. When you’re loading densified propellants, it is not an inherently stable situation.”

The Space Shuttle also had no way to get astronauts off the pad in the event of a fire or explosion. Also, Boeing is a competitor to SpaceX and Boeing is doing a full media push to downplay what SpaceX is doing.

Musk wants to do point to point suborbital transport with his new rocket coming out; for many reasons that is not going to happen on the scale he needs to make it profitable. The BFR is going to be very late and probably won't fly before 2024 (six years from now). The New Glenn probably won't fly before 2022 at the earliest. That gives the space industry 4-6 years to ramp up the demand for these launchers, which is also about the time that the US and Russia want to end the ISS. The future is exciting, but remember to keep the brain rooted in reality.