This is how movements are neutralized: those who should be allies are divided, infighting becomes rampant, and paranoia rules the roost. To combat these strategies, we must understand the danger they represent and how to counter them.
I respectfully suggest you're looking at the situation from the wrong elevation. We are fighting for something at a much higher level than the group or movement or political party. As a former Intel Analyst in the Army and person fully aware of how deep the rabbit hole is, I tell everyone who'll listen to operate as if there are spies and infiltrators everywhere.
When you operate with that assumption, you will drive forward towards the objective regardless of any obstacle. There is no way to divide and conquer in other words. We should not operate on a group or movement level. When we do that, we allow the tactic you are writing about to be effective. Don't operate in that way then.
Instead, operate with the end objective in mind at all times and regardless of the personal or group consequences. Every single individual does this, and then the people working in that way towards their combined goal can never be stopped. The only way to stop them would be to kill them all.
Also, as a PI I look for inconsistencies. I recommend everyone watch for inconsistencies. By inconsistencies I mean to look for people's actions not matching their words. Are they taking actions that are consistent with the end objective of maximizing individual liberty or not? Are they working towards the same end goal as me or not?
People can lie and fake it for years. Trust me. I've seen it happen and have been a victim to such people. If you continually and repeatedly verify people though, eventually you'll see cracks in their facade. You will begin to see minor inconsistencies. The common problem there though is the more close you are to the person, the more intimate you are with them, the less likely you are to pay attention to those inconsistencies.
I see inconsistencies in people who call themselves my friend. Shall I ignore those inconsistencies? No, absolutely not. I will not. Why? The objective I have is worth any price, remember? I will not focus on unity over objective. I will not ignore inconsistencies for a supposedly "greater good." If a person is being inconsistent, they should be called out immediately once that inconsistency is recognized.
We want to win, right? How can we win through a false unity? Never forget what Lenin once said. "The best way to control the opposition is to lead it ourselves." How do you know when that is happening? You see inconsistencies in the people attempting to move to positions of leadership. That's how you do it. No individual or group should be excluded from the process either. Trust but always and repeatedly verify. That is how we drive forward, step by step if need be, towards our objective.
Individual liberty is worth that price too. We must be vigilant. Asking to focus on unity instead of the primary objective too is not the best strategy.