Why go public with this? If anything, this is a contractual issue between JPMorgan and the API user. API usage terms should have been spelled out in contracts.
Because there is value in ensuring the public knows their use of Plaid is adversely effecting the banking system. Plaid in it's original incarnation was a straight up ToS violation for most financial firms, as they used privileged credentials to scrape the User's transaction history far in excess of what would be expected or reasonable.