Do any "spoiler theorist" Democrats and Republicans actually believe in free and fair democratic elections?

As a Green I have had so many accusations of "spoiler!" and whatnot thrown at me by rabidly partisan Democrats (one person has even said recently that Ralph Nader should be in jail...), and I'm sure Libertarians have had the same issue from Republicans. But surely a democratic election isn't such if it is limited to the same two political parties forever and ever more, as spoiler theorists seem to want. So I'm curious as to whether such people actually do believe in democratic elections but haven't realized the damage they are causing to the idea of them, or they genuinely don't believe in them but only the above restrictive Two-Party system?