To add to @young99's answer, the first half here means
(now) stop doing that.
才 takes on the meaning of "not (necessarily) (a lot of) others but this", i.e. a form of (exclusive) emphasis. Here it acts on the word 这, "this".
It corresponds to こそ in the original Japanese, which also places emphasis on a certain thing.
Idiomatic English might use "that" for this occasion, but here 这 is used to refer to something not necessarily close to the speaker, but which the speaker considers themself to be about as close to (or have about as much access to) as the other side (the listener) is / does. In the context 这 refers to a comment someone else has just made -- the rationale for using 这 is that the speaker kind of puts themself together with the listener on commenting the topic. To distance themself from the listener or the thing being referred to, the speaker could also use 那 which refers to something far from the speaker and close to the listener. I guess the translator did not use 那 because nothing in the original text is suggesting that the speaker is doing this.
People also use 这 in this way in many other contexts, even in a phone call or a video call when the speaker and the listener are far apart. The choice of the pronoun doesn't necessarily show agreement, distance, or relation, because any of these could be a reason of the pronoun choice. For example, 这 can be used because both parties are on the same topic, while 那 can be used to low-key indicate that the thing is more related to the listener's side (such as it is the listener that made the suggestion in question, and not (necessarily) that the speaker disagrees).