This summary is not the rule. The rule text controls.
If you have a lawyer helping you with a legal matter, the lawyer on the other side of your case is not allowed to contact you directly about that matter. They have to go through your lawyer instead. This rule protects people from being pressured or tricked into saying something harmful to their case when their own lawyer isn't there to help them.
The only way the other lawyer can talk to you directly is if your lawyer says it's okay, or if a judge or some other law specifically allows it. This rule applies as soon as the other lawyer knows you have legal representation for that particular matter. It doesn't matter if the other lawyer thinks talking to you would be harmless. They still need permission first.
This rule exists to keep things fair. Lawyers are trained to ask questions and make arguments in ways that can work against someone who doesn't have that same training. By requiring lawyers to go through your attorney, the rule makes sure you have someone looking out for your interests during any conversations about your case.
