No, but "sane Christians" can differentiate between calling for laws against queer marriage or teaching creationism in biology class, and knocking down a 50 or 100 year old historical marker because it had a religious symbol incorporated in the design.
Yeah, yeah, yeah, slippery slope and all that. Well, slippery doesn't matter if you wear sensible shoes and pay attention, like mom told you.
Calling someone a fundie, here, is tantamount to calling them a fanatic. It also implies that anyone that doesn't agree with you wants "to use the goverenment as a lever to promote his religion," to use Maggie's definition. It also implies anyone agreeing with you is not a fanatic. All three are bullshit.
Fundie is used, here, as a deliberate ploy to discredit any opposition.
It's a cheap shot, grouping anyone with any religious beliefs, or even just an opposing view, with the most rabid and fanatical of the religious extremists.
That's like saying if you enjoy fireworks you're a disciple of Ted Kaczynski.