... many of the critical concepts (like 合気, for instance) really have no exact English equivalents. Moreover, even when a word like "harmony" is an accurate literal translation, the concept is not understood in the same way in the Japanese and American cultures.
And this is self-evident, or better to say, natural, to everyone who works with historical texts (or facts). Texts from other times or/and other cultures can only be understood referring to their context.
E.g.: ki which is often understood as something "supernatural", belonging to the world of gods and religion, or at least being kind of mysterious, is an everyday term and phenomenon in it's original context. And aiki originally is just a techincal concept.
Not long ago I talked to a Japanese woman who was very astonished to learn that a lot of thoughts and phenomenons are seen as "spiritual" or even "religious" in western contexts.
It helps to regard that 合 can not be translated with "love".
But it may help also or even more, to take look to texts like "budo" and to see that terms like "harmony" or "love" are used different from the christian/western understanding.
So the "budo of love" can mean to "punch the opponent to his face with full force". (cited from my memory) It is simply obvious that "love" in this context does not mean the same as "love" in a christian understanding. (Which is the origin of the understanding of love in a modern-western context.)
It also helps a lot when remembering that terms like "love" and "harmony" where used by O Sensei already in 1925, which was also the year of his famous "enlightenment". Please look at his art in that time. (Which wasn't even called aiki budo then.)