Democracy is a tool. Voting is one action of use of that tool. The tool can fit one use case and not another. Tools, including democracy, aren't sacred institutions or panaceas that fix all.
A hammer is a tool. It can be used to build a wall. You can hammer a nail to help make a wall stronger. When the building you are in is on fire hammering that nail to build a wall to slow the fires spread to you does something. It's not the same as welcoming the fire in. But it won't magically save the building through participation. Building more and more firewalls doesn't stop the situation from continually getting worse.
So, hammering your one nail (or voting) might be one action in an effective strategy to deal with an issue, but it can't be the whole solution and only action.