You probably want to remove the URL from the text query parameter component when constructing a Tweet web intent URL and encode parameters according to RFC 3986 (%20 vs +).
text=Airbnb+Disaster+Response+https%3A%2F%2Fwww.airbnb.com%2Fdisaster-response
&url=https%253A%252F%252Fwww.airbnb.com%252Fdisaster-response
&related=airbnb
The url query parameter fills a share text component. The text component is pre-selected in web browsers for easy editing before sharing; the URL parameter is placed separately.