There is an immense amount of written communication involved in a programming job:

• Commit messages
• Bug reports & debugging discussions
• Design documents
• User documentation
• Project documentation, READMEs, internal dev documentation
• Project announcements
• Comments & in-code documentation
• Making complex situations simple for stakeholders
• Handling support tickets
• Mailing list discussions

Software engineers must learn to write well in the same way that they should also learn how to stay organized — they avoid doing so to their own detriment.