Don't you hate it when an employer doesn't contact you to let you know about their decision after interview?  ?

It is quite common not to receive feedback. Unless recruiters have automated tools to do that, this will keep being a challenge for many employers.

Nah.  They have their reasons for not doing so.  Although, likewise, they shouldn't come crying when you do the same to them.  The double standard is alive and well, ain't she??

Nope

If they don't contact me it means I didn't  get the job. I move on

No.

Their decision is no, unless you hear from them.  It's not too hard to figure out.

You want to continue looking for a job, until you have a signed offer letter or you started work.

Considering each job posting gets an average of 200 to 300 applications and they interview the best 50 applicants,  no they are not obligated to call every applicant to tell them they weren't picked. 

Yes, unfortunately this seems the normal behaviour now and there is no excuse as they can just send one email to everyone who has not got the job

No, they usually don't contact you if you didn't get the job that's normal and you shouldn't let it get to you. I would be disappointed if I didn't get the job, but I wouldn't hate them. 

The employer isn't always right. They don't know who is going to be the 'perfect' fit for the job.

No.  Not at all.  They aren't working for you.  They are busy.  They don't have time to contact every person they interviewed.  If you don't hear back, figure you didn't get the job.

Oh yeah, in this case the Employer is always right. but not by my standards, they very well should give everyone a call back regarding a decision for a Job opportunity that they also wanted your time for, or wasted your time for. Sometimes they will, but it is rare especially if they said they wanted to choose you, but chose someone else that was there first.