Rambam/Raavad on dunking matzah in charoset

Rambam (Cu"M 8:8)

בַּזְּמַן הַזֶּה שֶׁאֵין שָׁם קָרְבָּן אַחֵר שֶׁמְּבָרֵךְ הַמּוֹצִיא לֶחֶם חוֹזֵר וּמְבָרֵךְ עַל אֲכִילַת מַצָּה. וּמְטַבֵּל מַצָּה בַּחֲרֹסֶת וְאוֹכֵל

Raavad on the spot argues and writes in very strong language (as Magid Mishne takes note of), "she'zeh hevel."  

Sefer haManhig writes that matzah and charoset cannot go together, as matzah is a symbol of freedom, but charoset is a symbol of slavery, as it relates to the mortar used for bricks.

What is this argument all about?

In his sefer on inyanei Pesach, R' Wahrman z"l quotes the hesber of the Aderet that tries to make this l'shitasam:

The Rambam and Raadvad in Hil Teshuvah (ch 6) discuss (see here) why the Mitzrim deserved punishment when Hashem had decreed that BN"Y would have to serve as slaves in galus.  Rambam says that although the BN"Y were destined to be slaves to the Egyptian nation, each individual Egyptian had the choice whether he would be one of the people who would enslave a Jew or not.  Raavad answers that although there was a Divine decree of slavery, the Egyptians went above and beyond the norm in the harshness of their persecutions. 

We know that Klal Yisrael spent only 210 years, not 400+ years as slaves in Egypt.  The reduction in the number of years happened because the Egyptians worked us so intensely that those 210 years were the equivalent of 400 years of servitude (see this post).  

The Rambam l'shitaso views the harshness of the slavery as the key that unlocked the door to our getting out of jail earlier, and therefore, the charoset, the reminder of the bricks and mortar, goes with the matzah as a symbol of freedom.

Raavad sees the harshness of the servitude in a purely negative light, as the mechayeiv of the Egyptians.  Either he holds we got out earlier for some other reason than the severity of the slavery, or even if this is the reason, the unwarranted and unjust pain and suffering outweighs the positive outcome of leaving early.