The apparent meaning of the author’s words is that there is no difference between their being immediate, adjoining neighbours or not adjoining at all. That is correct: even if there is a street between them and the Muslim, they must not be allowed to build higher than him, because this entails humiliating the Muslim and exposes him to possible harm. A person in a higher building can look down upon one in a lower building, but not vice versa. We do not trust these disbelievers, and for this reason they are prevented from building higher than a Muslim.
But if the Muslim consents and says, “I have no objection,” are they still prevented or not?
The answer is: Yes, they are prevented, because the right involved here has an element of Allah’s right. Moreover, this Muslim exists now, but he will not remain forever: he may die or move away, leaving the building higher than those who come after him. Therefore, a building may not be higher than that of a Muslim, even with the Muslim’s permission and consent.
If they acquire a building from a Muslim that is already higher—meaning, they purchase from a Muslim a luxurious, tall building—must we demolish it?
The answer is: We say: You have the choice either to demolish it or to rescind the sale.
If they say, “Then rescinding the sale is easier for us than demolition,” but the Muslim refuses and says, “I do not wish to rescind the sale,”
we say: We compel you, because you sold them a building which they may not be allowed to retain. You are the one who acted unlawfully, so we compel you to rescind the sale.
His statement, “but not from making it equal to his,” means that they are not prevented from making their buildings equal in height to those of the Muslims, because they have not built higher than the Muslims.