I agree. The original sentence probably makes sense in context for a reader who read the docs from the beginning. I didn't read it, but I assume the author already introduced similar ways to "render a view", so saying "really just another way" implies the new one isn't fundamentally different and not all that important. On the other hand, it can sound annoying for a reader who landed to this page from a search engine. I think it shows the somewhat inevitable tension between documentation as a standlone work and documentation as a random-access reference.

Nevertheless, as the author said, I do find removing the superfluous "just" after the first sentence is warranted. The original text used 3 "just". One "just" in the first sentence is enough. And definitely don't write "painfully simple".

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On second thought, if this is what you want to express by using a "just", a better idea is to say it explicitly, let me try...

> Mailers is yet another option to render a view. similar to the HTTP module. Instead of rendering a view and sending it over the HTTP protocol, they send it out through email protocols instead.

This can be the better alternative of both versions. Be straightforward, don't use subtle language in a technical document.