Why can't I play forza horizon 5 without buying game Pass when I owned it before it was...

Hi Conor, my name is Rodrigo. I'm an Independent Advisor and a member of the Microsoft community and I'd love to assist you today.

To play online games you need a Game Pass subscription.

The Game Pass Core subscription allows online multiplayer.

For more information on the Game Pass Core subscription: https://www.xbox.com/xbox-game-pass/core

so are all the microsoft games like forza and halo included?

Forza Horizon 4 is a Play Anywhere title (not sure about Motorsport)...would make sense for Horizon 5 to also be when it releases.

Halo:MCC is not a Play Anywhere title and requires buying separately for console and PC (I own the console version and would have to pay to play the PC version if I wanted to own it)...however, it is on Game Pass for PC and console so if you own the UGP you can play it on either

I think Halo: Infinite will be Day 1 on Game Pass (not 100% sure though) so you can play it on console or PC if you have GP without purchasing. Halo 5: Guardians can't be played on PC/laptop as it wasn't made available on that platform (for some unknown bizarre and completely illogical reason)

I bought forza horizon 5 but I need the game pass to play it with friends why?

Can I get FORZA HORIZON 5 for free without buying or join Xbox game pass

Not legally, no.

If it was possible, then it would be pointless them selling it or having it on Game Pass as everybody would avoid paying.

You might be able to download a playable demo of it nearer the time as the Horizon games usually have one about a month or so before release

The screenshot showing "included in this bundle" will only show a few as there are too many separate DLC items in it to list fully as there are 11 separate things in it:

"The Forza Horizon 5 Premium Add-ons Bundle includes the Forza Horizon 5: Hot Wheels expansion, Car Pass, VIP Membership, the Welcome Pack, and the second game expansion once it becomes available.
The Forza Horizon 4 Ultimate Add-ons Bundle includes the Car Pass, VIP Membership, Formula Drift Car Pack, Best of Bond Car Pack, and the Fortune Island and LEGO® Speed Champions game expansions"

But, as noted above, the DLC does not come as part of Game Pass Ultimate...you can buy the Bundle and play without owning the game (ie using the Game Pass version of the game)