As David Soul said, they were two men who loved a each other who just happened to be cops. Shotgun Britton, make up artist on this and many shows said, "I never seen such chemistry!" And if course, the bloopers have that voice over calling them, "French-kissing, prime time homos."
I saw Starsky & Hutch when it originally premiered. We never thought their relationship was strange regarding their closeness. Never commented upon. I have brothers and that is how we are.
Today, decades later, do not see anything unusual in their camaraderie. Sometimes, non-blood linked males become as close as brothers.