That's because their definition of "compromise" is very flawed, and purposefully so.
A compromise involves a situation in which either party gives a little and gets a little. What did we get in exchange for the 1934 NFA? Nothing. The 1969 GCA? Nothing. When the FOPA was set to pass in 1986, they were appalled that there were provisions that might actually benefit gun owners, so they poisoned it with the Hughes amendment.
What did we get in exchange for the Brady Bill or the Assault Weapons Ban? Nothing. In fact, the little negotiation the NRA was able to do to ameliorate the effects of those bills (no persistent registry, 10-year sunset on the AWB, letting people actually keep property they lawfully owned prior to the law) was scorned by the bills' sponsors. Going into the vote, they crowed about how great those laws were. Once the President signed both bills, they claimed they hadn't gone far enough.
The important thing to remember is this: gun control is an incremental strategy, with the end goal being as close to total civilian disarmament as possible. Any "compromise" its advocates offer is simply a pause along the way. They simply can't be dealt with in good faith when they're so dishonest about their intentions.
