The insolence at the time preceding the Messiah comes about
The phrase "insolence at the time preceding the Messiah" refers to the words of the Talmud (Sotah 49b), which states: "In the footsteps of the Messiah insolence will increase". The Hebrew term chutzpah can be translated in various situations as "impertinence" or "insolence". However, in this case it has a more positive connotation; here, the term implies audacity, or the ability to persevere in the face of adversity and to achieve one's goal with absolute resolution.
The term chutzpah was used by Zionists to emphasize the free, bold, pioneering character of the first Zionist settlers in the State of Israel, as well as their psychological superiority over Jews of the Diaspora. Rav Kook, who identified the Zionism of his times as the beginning of the Era of the Messiah (the Talmud's description of the increase in chutzpah clearly correlated with the psychological self-determination of the first Zionists), uses the word to describe the audacious departure from religion on the part of the founders of Zionism. See also sections 68 and 107.
Rav Kook speaks here as much of the contemporary cultural thought (which is manifested in science, ideology, philosophy, sociology, and so forth) as of the projection of this state of things onto religion. The world has now developed and matured to the point where people need a complete picture (such as the modern scientific paradigm or the model offered by physics, in which all parts of the whole are determined by general laws, and it is those laws that humankind strives to discover); the contemporary mind will not tolerate a model in which unrelated parts exist in themselves, disconnected from general principles or philosophies.
In principle, this contemporary state of affairs is a positive thing ("the world has progressed"), for it advances humankind. But it has negative side effects as well. Many individuals in contemporary secular society regard religion in such a way that they generally support its essential values and ideals, but reject those "details" that they see as disconnected from the central goals of the religion. For instance, some people recognize the important idea behind the Sabbath as a weekly day of rest - and even extol the ancient Jewish religion and proclaim the ideal of a weekly day of rest; at the same time, they reject the concrete laws against Sabbath work, as they do not see how these "details" are related to the principle of "rest." Or, for example, while extolling the moral justice proclaimed by the ancient prophets of Israel, some individuals reject the prophets' exhortation to observe concrete commandments, as they see these as unrelated to the general principles and ideals of moral and social justice.
Secular Zionists at the time of Rav Kook saw many of the commandments of Judaism as discrete parts, disconnected from general ideals, and they therefore rejected them.
Teshuvah means repentance, return, the rectification of sins and flaws, the lifting of the world to God.
In other words, the rejection of religion in the late nineteenth and early twentieth centuries reflected not a decline in the spiritual level of the Jewish people (as many in the religious establishment claimed), but, on the contrary, a higher demand for spiritual systems, for a clear understanding of the connections between the concrete aspects of religion and general spiritual principles. At the same time, in the world of Torah studies, no similar intellectual movement took place. Thus, the public consciousness asked for a more advanced and deeper understanding - and the world of the Torah had no adequate response. This is what led to the "terrible destruction" of the traditional framework of Jewish observance.
That is, a "lower remedy" - a simple call to observe the commandments, to return to the earlier Judaism that those people had rejected - would not help.
Developing people's spiritual intuition and raising the level of Torah study.
That is, until all of this is understood by and evident to the average person.
"Universal teshuvah": This refers to Rav Kook's concept of the universal elevation of the world to God, described in detail in Orot haTeshuva.