Then think again. It gets attention because it was added post factum as a stretch goal when most already made their decision to support the campaign. That's why.
Why should money be wasted on exFAT if for example they can be used to improve the browser or any other part of Sailfish which does not involve patent encumbered or closed stuff and still needs a lot of improvement?
If paying for exFAT patent lock-in would have been explicitly included in the funding sum from the start, some wouldn't have contributed to begin with for instance.
And all those claims that exFAT is absolutely needed and so on are false. It might be needed for some, and completely not needed for others.