#1 - In the middle of an investigation, LE isn't required to release any and all information they have. You know that, and most people don't expect LE to release all their information. Negative information as you stated? Hmmm, the same info can be spun in different directions by each side. It just happens to be that, at this point, Jason and his legal team have elected to make no comments, so their "spin" isn't on record just yet. They can counter the relatively few official comments whenever they want to! We'll listen. If they don't want to put their version of events out for the public until a trial (IF and when Jason's charged), then they can try to shred everything that's been stated by LE and the DA in the courtroom, where it really matters.
#2 - It's my impression that you were not there, on scene, when Jason and the Young family arrived and were met by investigators. If you weren't, then you've been given a version of events from family members of the #1 person of interest. Would they be scared, bewildered, angry, defensive, concerned, etc. about what has transpired in a very short period of time? You bet. Do you honestly think you got a neutral description of events? In my personal opinion, it probably wasn't a factual replay. Not faulting the Youngs for that, as they were pushed into a foreign situation for them. Being questioned by LE can be intimidating just on a traffic stop, let alone in the early stages of a horrible homicide investigation.
#3 - your use of "grilling" over and over gets old, at least to me (and maybe only me). Grilling, interrogating, interviewing, questioning, etc. Yep, all can be expected in a homicide investigation. Some detectives and LE may start out calm and good natured and caring; others, not so much. Some are gruff, neutral, grumpy, direct, coarse, and did I mention gruff??? Some can also be condescending and arrogant. Different demeanors and personalities. Ever wonder why some become more direct and appear less soft than others? Maybe because of the years of being lied to, people stalling, being defensive and unhelpful? These officers want to get to the bottom of the situation and just want to cut to the chase, so to speak. Sometimes it's not at all like you see on TV and sometimes it has shades of it. "Grilling" as you like to say is not illegal. I feel a little bad that the Youngs were subjected to it, but honesty, looking back they shouldn't be that surprised.
For all the negative spin you put out on the message boards regarding your take of LE's role on that first night and what they've mentioned in the media (which has been very limited, BTW)...IF Jason is innocent and LE does find the real killer, will the Youngs be thankful to them for solving the murder of two family members?