Bonn — The largest antinuclear demonstration of them all scorned President Reagan's nuclear ''zero-option'' initiative Nov. 21 - and raised the question: Is it already too late for the American President to change his trigger-happy image among the European public?
After a year of campaigning for the presidency and almost a year as president on a platform of increasing American military power and confronting the Soviet Union, Reagan has gained a strong image of belligerence in Europe. One speech emphasizing the importance of peace has done no more than dent that image.
Thus the 300,000-350,000 festive marchers who gathered in Amsterdam Nov. 21 paid no attention at all to Reagan's new offer to forego the NATO nuclear missiles planned for mid-1980 deployment if the Soviet Union would dismantle its already existing comparable-range, land-based missiles. Instead, the group concentrated - as have huge antinuclear protests in Bonn, Brussels, London, Paris, and Rome - on opposing the future NATO deployments.
Some banners in Amsterdam called for both ''Soviet and US nuclear missiles out of Europe.'' The main target of the march, however, was clearly the American and NATO weapons. Already the antinuclear movement in Holland has achieved success in effectively blocking acceptance of the 48 new NATO missiles planned for Dutch deployment; the movement now sees its further mission as spreading this refusal to all of NATO.
In West Germany somewhat more antinuclear sentiment has been addressed to Soviet President Leonid Brezhnev on the eve of his Nov. 22-25 visit to Bonn. In a small demonstration in the West German capital Nov. 22, ecology-minded ''Greens'' criticized Soviet as well as Western nuclear overkill. Several conservative groups also demonstrated in West Germany both against Soviet nuclear weapons and against occupation of Afghanistan.
One of the major West German antinuclear groups, the Action Reconciliation/Peace Service, sent a thoughtful open letter to Mr. Brezhnev. In it the group asked Brezhnev to consider what steps the USSR might take to reverse the nuclear arms race in Europe. It pointed out that both East and West think they are arming only for defense - but that their weapons look threatening to the other side. The letter called for more ''transparency'' and information about Warsaw Pact weapons in an effort to build confidence. The only concrete measures it proposed were a slowdown and then a moratorium on stationing new SS- 20 missiles.
A second major antinuclear group, ''The Krefeld Appeal'' called on Brezhnev to begin a moratorium on SS-20 deployment with the opening of the American-Soviet arms control talks in Geneva Nov. 30. The Kremlin might find such a move attractive, since it has offered various moratorium proposals in the past that Western officials regard as freezing the Soviet lead in European nuclear missiles.
The weekend antinuclear demonstration Moscow is least likely to approve occurred in the Soviet Warsaw Pact ally of Rumania where several hundred thousand reportedly marched in favor of reduction of nuclear weapons by both East and West.