''Everybody's on MacTavish's side in the sense that he should be playing,'' said Frank Leonard, 24, a student from Hyde Park, Mass. ''It's not for me or anybody but the courts to decide his guilt. But I think he carries a lot of responsibility along with his job. I don't like to admit it, but I have to say that I think he should be more careful than the average person in what he does.'' ''I think he should be playing and that due process will take care of his case,'' said Jim Friedman, 39, a real estate developer from Wayland, who was at the nearby Dockside restaurant. ''But I will say this, if I'm drinking tonight, then I'm going to take a cab home, even though my car's parked right out front. I think he could have afforded a taxi.'' He Is Pleased on Career Mark

After the game, Mr. MacTavish conceded he was nervous getting back on the ice, disappointed that the team had lost and excited that he had reached a career- high mark of 20 goals in a season. But on the advice of his lawyer, Bob Murray, he has not talked about the accident, or the hours before it.

Jim Craig, a former Bruin teammate of Mr. MacTavish, is familiar with the public scrutiny athletes face. As goalie of the 1980 United States Hockey Team, which won an Olympic gold medal, he was a favorite of American fans, particularly those from Boston, his hometown. But the praise turned to criticism when he did not live up to expectations in his professional debut. The reproof sharpened two years after the Olympics, when he was in an auto accident that left one woman dead and another critically injured.

In Mr. Craig's case, there was never an accusation of drunken driving, and he was acquitted of all charges.

''This day and age, athletes are used as an example,'' said Mr. Craig, who is now with the Minnesota North Stars. ''You can't get away with anything. He gets in the accident and it's on the front page, and when he goes to court the first time, that will be on the front page for a week and when there's a decision, that will be on the front page for another week. He's the clay pigeon now and there are 20 shooters there ready.''

District Attorney Kevin Burke said his office was handling the case routinely. ''We have three other cases pending with similar factual circumstances,'' said Mr. Burke, ''and we have treated the MacTavish case no differently.'' Proposals in Legislature

The Massachusetts Legislature is reviewing proposals to strengthen its laws governing drunken driving. The law now requires a mandatory one- year jail sentence, with a maximum of 10 years, for a felony conviction of vehicular manslaughter.