The Catholic Church, I guess The Vatican, has been ok with vaccines grown in fetal cells for many years. This is not the Catholic stance, it is one group of Catholics. The fetal tissue argument is an old schtick of the anti-vax crowd usually not used by the Catholics, but by the Evangelical more extremist.
What I have noticed is in the last few years anti-vaxxer messaging has gotten to a lot of Catholics who previously were not infected (pun intended) by uninformed crazy talk. The anti-vaxxers were all over the internet two months against Pfizer and Moderna because vaccines are made from fetal tissue, which is completely false for those two vaccines, at least this time they are right that fetal cells are used in JNJ, but it is a very very old line of cells from willingly aborted fetuses.
See this document bottom right that the Catholic Church and Southern Baptists approve of the JNJ vaccine.
I think we should not get in an uproar with this situation and just agree JNJ uses the cells, and reinforce that Pfizer and Moderna do not, so anyone with an ethical objection can get the vaccine they are comfortable with. I emphasize again the anti-vaxxers are saying all vaccine use fetal cells, so I think lets just be honest and not spin our wheels trying to change anyone’s mind about the ethics and just give then the solution they can easily live with. The real anti-vax people won’t take any vaccine, but the people willing who are just being influenced can be reassured they do have a choice of a vaccine that is safe and free of any moral conflict.