[ImpactBreaker]

Ayu (or her directors) love to play with contradictory, ambiguous stuff. If anyone remember the WHATEVER PV, the song has lyrics about hope and a good message but the PV shows despair, hopelessness, and that's not worth fighting for your goals. Ayu has a serious expression and does not blink the whole video. The PV is completelly contradictory with the lyrics. But not only the PV. The M version of WHATEVER (the one played in the PV) also has a macabre melody. The intention was obviously to make it contradictory.
So I wouldn't be surprised if the intention on Because of you was to make that thing ambiguous. A contrast between purity or dirtiness (depending on what the person who's watching will interpret the video) the anime in black and white, contrasting colors. Maybe the intention was truly to make it ambiguous, contradictory in order to shock but also not to shock because it's all up to your own interpretation in the end. The lyrics itself kida seem to have contradictory stuff on them when Ayu says:

My eyes met yours again, we talked a little
My heart throbbed and I hid my feelings behind a smile
As I was afraid I might not be able to go back to the times
When I had not known you

Kinda contrasts with:

I can't think of anyone but you
I can't think of anyone but you