I don't see the problem. These folks can play, some of them came out of Yuba Ire, a great rumba group from Puerto Rico and some come from the bomba tradition. They have a different style but it is original, keeping traditions alive (both Cuban and Puerto Rican) while adapting to modern forms like midi and synthesizers. I have not seen midi bata before. That young lead singer Kathy Cepeda can sing, although unfortunately I don't see her in their more recent videos. It seems they have lost some of their other members too since that 2015 video, I hope they can bring some of them back into the group.
I am not into electronic music myself either, and in my younger days, I totally agreed with you to keep the electronics and folkloric music separate. In 1975, a physics professor of mine was inventing a synthesizer and asked me to play a conga for him to record so he could model the waveform and program it into his synthesizer. I refused, because I believed the sounds of the instrument were natural and cultural and represented thousands of years of development, and I did not want to participate in the creation of a technological form of music that could potentially replace the role of live percussionists in music by people and machines that had no understanding of or interest in the history. Ideologically, I am not a Luddite, but I do believe in preserving the human real time interactions that are the essence of improvisational music, as well as the importance of folkloric music in passing on an oral history that is not on TV, in the history books, or even in forums like this. He was disappointed but continued on without me (no his name was not Moog). Looking back, I am glad I put up that little tiny bit of resistance, and I still believe in keeping the folklore human. While I have accepted metal tuning lugs, polyurethane and digital recordings, I still don't like plastic skins or fiberglass drums.
In spite of these kinds of purist considerations, technology is hitting Cuba too and we are getting older. Anga liked to have a DJ performing with him. I even heard an interview of Rafael El Niño Pujada Navarro, lead singer of Los Muñequitos, saying his kids listen to regaeton more than rumba. Carlito el Social the lead singer of Columbia del Puerto, one of the best rumba groups in Cuba, has taken up rapping and regaeton.
Think about it. Is this so different from the rumba de cajon that developed using boxes, furniture and spoons and helped preserve some of the African culture through the most repressive of the racist colonial times (Tiempo de España) when drums were prohibited? People use the medium available and invent new ways to keep the flame alive and get through to the younger generations, which is what really counts. Midi batarumba has some analogies with rumba de cajon. Plus some of the orthodox religious activities in Cuba and elsewhere are not so pure either, and some have become corrupted and commercialized, like many other religions. Just go to Callejon de Hamel in Cayo Hueso next time you are in la Habana. Religions are businesses too.
And the rumba keeps evolving as well. Pancho Quinto considered himself an orthodox rumbero. Some people hated Rapsodia Rumbera when it came out in the mid 1990s, claiming that is not rumba, what happened to the salidor? But ten years later those same people were trying to learn "guarapachangueo". Plus Ife is keeping the anti-colonial protest music and improvisation-within-clave aspects of the rumba going, different musical style but similar philosophy. Their 2020 video, done under lockdown conditions using lots of overdubbing and effects, has a song about the pandemic dedicated to the singer's cousin who died of COVID the day before the session. La timba no es como ayer. Pa'lante Ife.
https://www.youtube.com/watch?v=b2YWihRPtT8