A. Everybody is going to Moscow. If France is going to march, why shouldn't Moldova?
France and Russia have a different history to Moldova and Russia. France is not a former part of Russia's empire. France hasn't been on the receiving end of Russian gas and wine embargoes. France doesn't have 10% of it's territory occupied by Russian troops.
In fact, if France had had Moldova's history with Russia, it wouldn't be maintaining diplomatic relationships and it would probably be at war with Russia, as it's national dignity would dictate.
B. The parade celebrates the victory over fascism. If Moldova doesn't participate, it will be seen to support fascism.
At the start of the war, Moldova was part of Romania. It began the war as a component of a Fascist Romania homeland, and ended the war as a component of the foreign communist Soviet Union. The quality of governance and human rights observance probably didn't change that much. With reference specifically to Moldova, there is nothing to celebrate, and it's not about Fascism.
With reference to the wider European conflict, the end of the war and the defeat of Hitler is to be celebrated. The best place to do this would be Western Europe, where the commemoration would be treated with sensitivity. Participation in a jingoistic parade on Red Square would (unhelpfully) reinforce the old Soviet 'Great Patriotic War' mythology, rather than seeking truth and reconciliation.
C. We need to maintain good relations with Russia. Non-participation in the parade will impact on gas prices and exports.
Moldova has been kow-towing to Russia for twenty years, to no useful end. It didn't stop the Transnistrian secession, the gas wars or the accession of the Moldovan communist party to power. Seeking Russian favour at any price is a game that can only end in tears for Moldova.
By the way, gas prices are going up anyway and Moldovan products are already being selectively banned from Russian markets