don`t seek any hidden meanings if there are none.
The meaning is clear: those are gay colors and the message is that gays are good people.
Pretending that they are not there deliberately and not pro-gay is like claiming that a swastika on a Jewish grave marker is just four squares with four sides missing by mistake.
This is not an attempt to start another gay vs hetero fight, so don't go there. I am strictly on those colors as a social or political message which many may not want to see - along with other messages, however noble and progressive they may be to the artist.
If there were colors to express our hate of child molesters or love of motherhood, I still want park benches to be off-limits.