Actually, I don't believe that you can completely blame Microsoft for
enforcing standards by default. However, if you want it your way then do
this:
1) Go to the Tools menu and select Options....
2) Expand the Text Editor node and then expand the HTML node.
3) Select the Format node and then click on the Tag Specific Options....
4) In the dialog, select the Client HTML Tags node and expand it.
5) If "br" is not there, then select New Tag... and enter br into the
textbox and click OK. Otherwise....
6) Change the Closing tag dropdown to No closing tag and then click OK and
OK again.
From now on, you can now have <br> by default.
Please note that I only point the standards compliance only because at some
point in time it may be required by federal regulation due to ADA and some
similar requirements. Plus, by staying compliant, you have a better chance
of ensuring user-friendly renderings in multiple browsers. You may not care
about it, but it doesn't work right for your users, they may not come back.