In The Last Jedi, Snoke says “Finish your training... and fulfil your destiny.”
After this, Kylo kills his master and becomes a master himself.
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As the old Soviet joke goes, "Officer, I didn't steal those jeans. And they were dirty and all full of holes anyway!".
We don't know that they follow Rule of Two in the first place, in word or even deed:
Supplementary fact books show that Snoke had at least another apprentice besides Emo Ren.
We are given strong (but not yet canon confrimed) hints that Knights of Ren are Luke's former students that left with Ben Solo. If so, clearly Snoke was teaching them too
Finally, it can be argued that Kylo has no apprentices after killing Snoke.
Having said that, the rule of Two is not 1 to 1 associated with the Sith:
First, even the Sith didn't exactly obey it. For one thing, Sith before Darth Bane didn't. For another, we have tons of examples of Sidious/Vader violating it.
Second, Rule of Two isn't a "Sith only" thing. It's just a tactical/philosophical concept. As such, any Force user may act in the ways that follow such a rule, not because "they are following Sith ways" but because the rule makes a lot of sense (it did work out well for the Sith, after all).