Hello,
We absolutely understand your concerns regarding this, however, the issue is that these Forms are filled up by Real People who send out SPAM and not Bots (our Forms Processors are designed to protect against Bot SPAMs), which is why the reCaptchas are also passed. As a result, the Form Responses are successfully delivered.
An extra layer of protection is required to filter out words that you want to block when sending out Form Responses to your Emails. We are working on an Update for this and will send you a Notification once it is available. Thanks for your Patience.
Meanwhile, do let us know if we can help you with anything else or if you find any further issues with Canvas.