Two reasons:

The term pixel fucking. It's not about "fuck the pixels", it's "make love to pixels". It's about making one pixel changes to fine tune a design so it's just right. It's about the feedback loop "can you make this title a bit more pop?" what ends with increasing and decreasing a font size a number of times and in the end leaving it as it was in the first place.

Before Finch we all worked in a design agency and this was the term we used in the end of each project - the site is designed, freshly developed and now comes the pixel fucking - there are one pixel errors that need to be fixed. The designer changed his mind about some line heights and border widths. The client thinks that he knows something about design. The project manager has to translate it all to each person involved. The developer needs to understand it all and reimplement it numerous times. This whole process is pixel fucking for us and is the main problem we want to solve with Finch.

Originally the term comes from visual effect artist community. Here's how they explain what pixel fucking is - https://vimeo.com/213520878#t=516s (if you haven't seen it already, I recommend the whole documentary).

The second reason - we are a three guy team that tries to make a product for like-minded professionals. We did not wan't to make a corporate impression that there's a huge team behind the product or go the safe, inexplicable "Collaborate. Change. Together." way. So we decided to make the copy as we feel it and as wee see the problem we want to tackle. Our assumption was that seeing a "pixel fucking" title, visitors would understand what we are talking about or be intrigued to find out what we mean by that. But not be disgusted by a word, they, honestly, use every day. Lesson learned :)

Inline source maps for Sass are supported for now. The css to sass part is experimental right now, but we are working on a stable support.

That's the best tool for power users that understand the code and work alone. When you work in a team and even manage to teach your designer to use this, the change transfer to the original code is still manual and a mess :/