I have not even expressed an opinion about any of this, and I do not have one.
It is an interesting situation, but not relevant to me at all.

I raised the issue of infiltration from both right and left, and I raised the issue of Tory infiltration first. By many weeks.
No-one wanted to talk about it then.

If Harman really meant, " "Anyone – providing they are on the electoral register – can become a registered supporter,..." why did they then reject thousands who did apply?
They did not want people with different values to those of Labour.
Not right wing, not far right and not far left.
Those when identified were rejected, so not open to anyone.