Further thoughts:
The New Zealand perpetrator was a white supremacist who implicated Trump. This was juicy. It may be that the mainstream media (not FOX, which i haven't checked) is "liberal" enough at this point to be more comfortable sensationalizing the Trump angle than they are with fueling more anti-Muslim sentiment.
Right now it is a big assumption that the perpetrators were Muslim.
Sri Lanka has only specified "religious extremists"
There is a report that the government was warned last week that a group called "National Thowheeth Jama’ath" were planning to attack churches.
National Thowheeth Jama’ath is made up of "Syria and jihad returnees" and first came to public attention "when it was linked to the vandalisation of Buddhist statues"
I am getting that information from
an article proclaiming their innocence on a Malaysian website, though, which is also underreporting the casualties at 135.