If the rest of the pro-life movement held this view, abortion would remain legal forever because nobody would ever listed to pro-lifers. Fight the battles you can win. The birth-control pill is not something you'll ever be able to get rid of.
They said the same of slavery and many other things.
Your advice sounds reasonable on the face of it, but it is by no means essential. The "fight" for good never ends. There will always be battles to win, both big and small. And from a human standpoint there will always be battles lost.
In this case pro-lifers should be encouraged to speak as clearly and as truly as ever.