It is proper to yearn to be bound to the entire nation of Israel
A "preponderance of judgments" (gevura, din): scrutinizing the behavior of others for adherence to halakha and the Torah law. If one evaluates others in this way, one's smallness is revealed. Gevura is the "left side" (see a parallel statement in paragraph 67).
Inasmuch as many Israelis do not observe halakha, such a person will be unable to connect with this nonobservant society. The path proposed by Rav Kook is to observe the halakha strictly oneself, but refrain from judging others on the basis of their observance, as this would render impossible connection with other segments of society. Such a connection can form only on the basis of love (hessed).
What appears at the lower level to the person who judges surroundings based on halakha, in fact contains within itself a very important light - insufficiently "refined" perhaps, but very potent. And without connection to that level such a person lacks "fullness of light," without which that person cannot attain any higher level.
In connection with paragraph 126, we could say here that the person who judges others based on their observance lowers God to the level of simple "law," thus rendering God "small." (That is, such a person imagines God merely as one who punishes and rewards. In this way, a person brings down the highest divine holiness, and therefore cannot rise to the highest level and become one with the divine. See also paragraphs 129, 163, 184.)