The gemara explains that the torah uses the term "ha'ma'aleh" in the context of the issur shertatzim to indicate that this is a special advantage to klal yisroel and had Hashem only taken us out of mitzrayim for this alone, it would be worth it. The gemara continues to explain that although the reward for abstaining from sheratzim cannot be as great as ribbis and ona'ah where there is a strong yetzer hora, nevertheless since they are disgusting it is considered a ma'aleh of klal yisroel. Rashi explains that since these things are inherently disgusting, it is considered to be a ma'aleh for klal yisroel that they abstain from them and don't sustain themselves from things that are so repulsive.
R' Moshe (dibros hea'ra 15) is troubled by this. The only problem with sheratzim is that they are forbidden, but there is nothing inherently disgusting about them. Why are sheratzim considered to be a bigger ma'aleh than any other forbidden foods? - it is only the issur that makes it repulsive, not the metzius. To strengthen the question, we can cite the midrash that rashi quotes in chumash that a person should not say that they are repulsed by pork, rather they abstain only because of the issur torah. The same should apply to bugs, one should not necessarily be repulsed, yet abstain because of the issur torah.
It seems to me that rashi understands that sheratzim are inherently disgusting. You are what you eat. Therefore, it is a ma'aleh for klal yisroel that Hashem forces us to refrain from these foods.
R' Moshe suggests that the ma'aleh is somewhat different. There are many goyim who also refrain from eating bugs because they are disgusted by it. But, they don't check their vegetables for bugs. Abstaining form something because it is disgusting and repulsive has its limits, it won't cause you to search to find it. However, we abstain from bugs because of the issur and therefore make ourselves crazy to inspect vegies to find them. This is the ma'aleh of klal yisroel - the contrast of abstaining from issur vs. abstaining out of disgust. The effort put into staying away from issur BECAUSE IT IS ASSUR is the ma'aleh for klal yisroel.