I have not seen specific references describing what the red wine represent in the Seder, and why the red wine is preferred. I know Moses did not write about it, but the tradition of the cup developed traditionally for the Seder remembrance for the Passover of the blood sacrifice. My understanding is that it represents the blood of that sacrifice, but even if it is symbolical, how is it understood without being controversial and objectionable, because drinking blood is forbidden? Or the symbolical drinking of the blood should not be difficult? Please quote the references if any, with links for a better study. What does the red wine symbolize?
Shabbat 129a:14 מַאי צׇרְכֵי סְעוּדָה? רַב אָמַר: בָּשָׂר, וּשְׁמוּאֵל אָמַר: יַיִן. רַב אָמַר: בָּשָׂר — נַפְשָׁא חֲלַף נַפְשָׁא. וּשְׁמוּאֵל אָמַר: יַיִן — סוּמָּקָא חֲלַף סוּמָּקָא. The Gemara asks: What are these special needs of a meal? Rav said: It is referring to meat. And Shmuel said: It is referring to wine. The Gemara explains: Rav says: It is referring to meat because the soul replaces the soul, i.e., the meat replenishes the person’s strength. And Shmuel said: It is referring to wine because the red replaces the red, i.e., red wine substitutes for red blood.
In one answer, I saw a different symbolism of the blood.
Not only is it a Minhag those who say Yotzros on Shabbos Hagadol say it in there יין כי יתאדם למצוה הוא מקדם Translates as "Wine that is Red for the Mitzvah ahead" Not only that the Rambam sas you are not Yotzeh using white wine for kiddush( we do not Poskin like that) and the Mishnah Berurah adds Pesach there is another reason to remind us of the of the blood of the Jewish children Pharoh used to Bathe in.