How would you do it?
Design and Skin Customization
You can do this by modifying a couple of templates, in your profile_header.tpl, find this:
{if jrProfile_is_profile_owner($_profile_id)}
{assign var="from_profile" value="yes"}
{/if}
and change it to this:
{assign var="from_profile" value="yes"}
I'm not even sure how or why that if check was there, it is not needed.
Then in your header.tpl, change this:
{* MAIN MENU *}
{if !jrCore_is_mobile_device() && !jrCore_is_tablet_device()}
{jrCore_include template="header_menu_desktop.tpl"}
{/if}
to this:
{* MAIN MENU *}
{if !jrCore_is_mobile_device() && !jrCore_is_tablet_device()}
{if !isset($from_profile} || $from_profile != 'yes'}
{jrCore_include template="header_menu_desktop.tpl"}
{/if}
{/if}
That will show the main menu on the front end of your site but not on the profile pages.
Hope this helps!