Prime reason:
Life begins with conception.
These centers are not implanting everything they create. They fertilize multiple eggs to better their success rates (and then publish the online for marketing purposes). There are no guidelines being proposed on the IVF that I am aware of being implemented to use what is conceived.
The reality is that freezing eggs is just a "conscience -soother" for "we'll throw them out later when we can put enough distance timewise to say 'we don't have a choice'".
As an aside:
The federal govt has no business using taxpayer money to fund this practice. It is a private, elective decision.
Trump is worried about our falling population numbers but the ends do not justify the means.
I know the Left doesn't care about this and may even like it.
On the right, I think that a good number of people against abortion at a further, more obviously macroscopically apparent stage, rationalize that this is different. The programming of the pro-abortion propaganda of the past 60 years has spread to all regions and has impacted much of the general public.
Perhaps many just don't believe that it is life - (but then cannot say at what point it becomes life later when they can see that it is obviously life - this should trigger the realization that it always was life from the start at conception, but that requires the sacrifice of giving something up that they may want and so many sadly rationalize and try to bury the thought).
My suspicion is that I am in a minority on this issue, but popularity does not determine morality.