At the end of a marathon session at Google’s (GOOG) I/O conference Wednesday, Larry Page took the stage to tell a room that he is saddened when he reads stories about infighting and negativity in the tech industry.

This story will make him sad.

Page followed up by saying that Microsoft (MSFT) was particularly unhelpful. To wit: The same day as Page’s keynote, tech website The Verge obtained a letter from Google’s lawyers to Microsoft insisting that Microsoft stop offering its YouTube app for the Windows Phone mobile operating system.

The app in question went live last week. It allows users to block advertisements (an issue of some importance to Google), includes a button allowing users to download videos, and gives them the ability to play videos that are restricted on mobile platforms. These features violate Google’s terms of service.

On this issue, the companies have been at it for a while. According to Microsoft, Google has been blocking features that would allow a YouTube app to run properly on Windows Phone, and Microsoft has voiced its complaints to regulators in Europe and the U.S.

“Google often says that the antitrust issues with which it has been charged cause no harm to consumers. Google is wrong about that,” wrote Dave Heiner, Microsoft’s deputy general counsel, on a post to the company’s public-policy blog in January.

Microsoft has also been running an aggressive ad campaign accusing Google of violating its users’ privacy, and arguing that those who want to avoid getting “scroogled” should use Microsoft’s Bing search engine and Windows Phone platform instead.

Google has argued that Windows Phone users can access YouTube on the mobile Web and don’t need a dedicated app. In a written statement, a Microsoft spokesperson said that the company would work with Google to resolve the issue:

Code:

YouTube is consistently one of the top apps downloaded by smartphone users on all platforms, but Google has refused to work with us to develop an app on par with other platforms. Since we updated the YouTube app to ensure our mutual customers a similar YouTube experience, ratings and feedback have been overwhelmingly positive. We’d be more than happy to include advertising but need Google to provide us access to the necessary APIs.

Representatives for Google did not respond to requests for comment.

While Page acknowledged that Google and Microsoft have a difficult relationship, his comments were a largely sentimental recounting of his love of technology and his wish that the industry focus on “making things that don’t exist.” Being negative, he said, is not the way to make progress.