It's a squick factor issue. When you're trying to break down templates as small as possible, everything tends to become a bit icky in templating systems anyway. Consider -

    [% BLOCK foo %]
        <td>[% payload %]</td>
    [% END %]
    ...
    [% INCLUDE foo payload=something %]

in TT (perl's Template Toolkit, which I'm about 98% sure pkrumins is familiar with already), and then

    function foo ({ payload }) {
        <td>{ payload }</td>
    }
    ...
    <Foo payload={something}/>

Once you've got a bunch of them in the same file, I don't honestly find the JSX much different. The trick for me is to have the HTML in .js files that contain only pure functional rendering components - so when I'm editing those, I can think in HTML and just treat the JS as a slightly weird template syntax - at which point the squick factor mostly recedes.