As spiritcc on tumblr mentioned and I quite agree that it was a cultural thing. Such touchy-feely male friendship was the norm for the Soviet Union and can be seen in other Soviet era films. What now can be interpreted as slashy then was perfectly platonic. With the fall of the Soviet Union more integration with the Western culture took place, and now men don’t express their affection for each other as freely for fear of being misinterpreted :)

On the other hand, I do prefer to watch old Russian Holmes through slashy googles, hehe.