How about making the text file into a HTML file and then using the text-transform: capitalize property in a style sheet
Code:
<html>
<head>
	<title></title>
</head>
<style>
pre{
	text-transform: capitalize;
}
</style>
<body>
<pre>
amateur gay porn
hardcore twink sex
exclusive porn movies
xxx rated adult sex
</pre>
</body>
</html>

In the output, your list will be capitalized and you can just copy it to your clipboard.