The Sheriff is also supporting a targeted motive. He stated that the area was isolated to the extent that it is very unlikely that one just pulls up on the wrong person by happenstance. The isolated area would probably reduce a road rage scenario as well.
Other possibilities such as say, deranged individuals claiming a fishing spot don't seem very likely either. The victims were not commercial fishermen whose activities would have placed them in economic competition with another commercial fisher. Even with recreational fishing, there is nothing about the area that was exclusive or where individuals would incur great expense and effort to get there, only to see somebody going to "their spot".
As for being lured, it appears the victims knew the spot and had been there before, perhaps often. Likewise, they were clearly going there to fish, not have a meeting with someone. Though these aspects don't eliminate the lure possibility, they might reduce it.
Rather, I think the totality suggests somebody targeting learning of the target's intended destination (social media?), then inducing him, or forcing him to stop just short of it and attacking him. The attack continued when the other two victims arrived.
