Well if you ask me, is using the "label"conspiracy theorist a fallacy on his own. Its just a way of saying, i don't know what to say back, so il come with personal attacks.
When people do that, just point that out to them and give them a second chance to come with a good argument.
If they can't do that, then that means, they don't want to go in a discussion with you and then its better to stop right there.
People who will honestly go in conversation about anything, will listen to your arguments , or give another solid argument back, and will never use a fallacy.
Like what i did in this post, i could say this or that, without showing anything and then i would open a debate.
But i showed videos and links to show where i get the information from, then that would be difficult to call it as a conspiracy, because sources are there.
For that reason i only talk about subjects with people, who have an open mind and don't believe what they think could be possible.
Otherwise, i could might as well talk to a wall.