Thanks to Sanford Whiteman, the integration with reCaptcha is finally working!
The issue with my code was a capital letter in the JS file. After getting that fixed Marketo was able to properly get a response from Google in the webhook.
The issue was on this line:
lastReCAPTCHAUserResponse: recaptchaResponse
The "last" had a capital "L" in front so it never sent the response to Marketo.
Without Sanford's help I'd never find out I think 
Thank you very much again Sanford and if anyone need help with this integration I can give a bit more detail.
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