It's not that clear cut of a tradeoff. If Apple were to allow limitless sideloading of apps and that became the standard way that people installed apps on iOS devices, it would seriously limit their ability to keep the platform secure against malicious apps.

I'm not sure that's a valid concern given that Android has allowed that since its earliest days, and most people are content to just use the market.

But all you need is that one person to side load something malicious and everyone in their contacts may be compromised.

No no. I'm talking about keys to my phone alone. If I choose to trust my own certificate then that only impacts what software I can run on my phone. An app cannot "sideload itself onto all your contacts". This extends to the OS itself. Let me change the certificate governing the OS software. Only once you allow that do I truly own my phone.

2muchcoffeeman doesn’t say apps will migrate to other phones.

(S)he implies that your friend’s phone being compromised will leak data about you (email address, physical address, birth date, mails you sent, etc)

If you give your friend that data, it's out of your hands. If you don't want your email address or birthdate to be known, don't give it to anyone.

I pretty much opertate from the point of view that anything I send in an email or text is public, and temper what I write accordingly.

The problem here is social engineering. If someone says "click these buttons in your phone's settings, sideload our app, and you'll be able to do X" (where X is "pirate movies," "mine bitcoin," etc), a surprising number of people would follow the instructions, ignore any big red warnings, and end up with their device pwned. You'd need a way to make the certificate trust settings accessible only to those who know what they're doing.

Apple places their customers first and developers second. They build devices for humans, not the mutant lizard people from space who develop software.

I am a human, and I develop software. This is a moronic statement.

Gee, I was going for ironic, missed, and hit moronic. Close enough for horseshoes. :)

I've started referring to software developers (like myself) with intentional irony as "mutant lizard people" after hearing one too many times how a particular OS/tool/programming language needs to be designed "for humans" (i.e, n00bs with no prior exposure to it).

That would be a terrible idea. Isn’t that how JavaScript started?