To avoid this turning into a Senna topic, i’ll keep it brief.
Each generation of driver has progressively become more ruthless in how they overtake and defended their positions. This became natural as the sport gained more prestige, and money became involved.
Senna was not the first ‘dirty’ driver. However, he was one of the first champions to use dirty tactics. Other drivers had to become dirtier to beat him. The move at Estoril 88 was this http://www.youtube.com/watch?v=zznJjSncGCE – notice the pitboard guy who has to move out of the way when the incident happens!
Senna escaped most of the criticism though because of his godlike status – and his more human and emotional side. Further, when confronted, Senna could admit that he had done wrong.
Schumacher has always been somewhat robot like with his emotions and never admitted to doing anything wrong. Even if 94 and 97 were unfortunately misjudged defences, parking at Monaco was simply cheating. But he never admitted that. Hence he’s disliked by a lot of people, such as Moss. It doesn’t help that Schumacher won his first two championships in very dubious circumstances too – one with the incident with Hill and the other with a traction control button on his car (supposedly never used…)
I think thats why Moss has issues with him. Personally, I like Schumacher but thats because I can also see that behind his flaws lies a great driver – one who was the master of the sprint series that F1 became during the fuel pitstops era.