Are my parents trying to tell me to back off?

I think you are reading into his reply too much.  In my opinion, he was steering you towards a more knowledgeable person.  Thats all.  He does not want to steer you wrong and then him get blamed for any chance that your investment goes sour.  Not a bad idea to be honest.  I mean if it did go wrong.. he would feel badly.

"I’m not socially inept and I’m not afraid to talk to people (hello?? Yahoo answers!!)".

You said a couple things here that are kind of odd, esp the above.  Using YA doesn't prove you aren't socially inept!  In fact, the biggest cause of social anxiety is using social media or sites like this.  I'm just curious why this topic even cropped up. 

I'm also puzzled why you'd think he's jealous.  Of whom?  

It could be something as simple as him not wanting to be too involved in your financial decisions, because he'd feel responsible if you take his advice and it goes south.   Like you say, he has more experience in this area, but we are living in very strange times right now.  If you have enough money to be investing, have you considered talking to an account manager for some of the larger investing firms?  There's a ton out there, like Wells Fargo or Morgan Stanley, etc.  

I realize your issue isn't about investing but rather your dad.  Unless you've seen other things that puzzle you, I'd guess  this is one issue where he doesn't want to be too involved.  If you wanted his advice about cars or something it's very possible he'd act more like Dad.  Dads generally like it when they feel needed by their adult kids.  

Hello concerned one your dad is the grown and father more space? More patience more natural affection more time is what he needs to be practicing toward his child. You are not a bother you are a blessing hopefully he recognizes this and have a change of heart. Try to keep a calm heart and your peace and pray for strength to endure and courage to keep moving forward.

He wants to hear about your life, who you are dating, how work is.  If you want stock advice get a stock advisor, that is their job.  

"Small talk" is not STOCK MARKET SHlT!

I think he wants you to get more in-depth advice and information from a variety of sources so that your success or lack of it isn't on his shoulders. He's learned from HIS mistakes... likely thinks you need to do that same for yourself. In other words, he doesn't want to be in charge of your success... and he's right to take that stance. Maybe you could talk with him about the lawn or where'd he like to go for lunch. 

If you want to be in charge of your own fiscal success then quit demanding that your Dad do it for you or be offended if he doesn't want to. Your position is totally human but not particularly logical. 

what you were doing is not called small talk, small talk is asking if he and your mum are keeping well, about how you are getting on at work, who your latest boyfriend is - that kind of thing, you are boring the poor man to death talking about the stock market