Rabbi Shammah is a very liberal rabbi in the community. He’s from the old school of rabbis like Matloub Abadi.
His views shouldn’t be taken as representative of the community as a whole. He himself is a signatory to the takanah in any event.
This clarification is meaningless. The pashut pshat is that they used to have conversions of infants adopted, but with reproductive medicine and technology, this is becoming rare. The children of a ger are accepted, but that’s not the same as a ger being accepted.
There have been several cases of individuals sincerely choosing to be Jewish who were rejected from the SY community.