ToD, the last time the post got edited was on December 6th, way BEFORE the patch came out which removed the ladders. Or do you want to tell me that the developers deliberately left that paragraph in the rules for some reason?
Since the ladders got removed we can assume that developers agree with the majority of the community to not want to have roofcampers any more, so it would be the logical consequence to change the rules accordingly. We already have enough problems with roofs than can only be accessed by weird jumping actions which in many cases require you to simply
know where to jump, as it's not obvious and probably found out by accident. Adding a simply line to the server rules would at least stop roofcamping enabled by siege shields. The alternative would be to either ignore it and still have roofcampers to some degree (which can be really annoying for everyone else, even if they do bad) or to find another solution of siege shields elevators, which in any case again needs gameplay changes that require coding.
Honestly, just rewrite the server rules, it's a matter of 30 seconds