Regardless of how much money they spent to influence the outcome, from the viewpoint of one whose vote was devalued by the influx of illegitimate votes counted in other jurisdictions, with a direct effect on the outcome of the election and subsequent policy, yes, it was stolen. Paying someone to steal something doesn't make it any less larceny than paying someone to pull the trigger makes it less a murder.
Every treasonous goon who participated in conducting that theft should be deprived of their vote, in perpetuity, and granted a time for reflection, preferably behind bars or before standing on a scaffold.