There's genuinely no excuse for child neglect. There are reasons and ways to understand why they did what they did, but it does not change that they did neglect their child and hurt them. Ercella had reasons for how she ended up because she felt like her life was restricted and she was always made to bear expectations at the cost of her freedom. It can make anyone feel resentful, especially when they don't have an outlet.
Just like I also get why Vicente and her husband take her sudden change of heart with skepticism. Her actions made them unwilling to fully believe that she truly changed, and even if she did, they might consider it too late because it's already been years of neglect and they are already at the age where they can be considered adults.
What could have been solved with therapy can't be solved now due to how therapy doesn't exist in there.
But people trying to condemn her for changing her tune now and saying that she doesn't deserve to make amends after what she did are the most unreasonable ones here. She reflected on what she did and wanted to change herself, and is even proving herself to do so now that she had a second chance. She's trying and to dismiss that is utterly baffling.