No more Facebook Group Chat? How to Chat with Group now?

Facebook rolled out last week an another update, unfortunately this is not a good news for the users, especially those who loves to chat with group. The quiet update is to remove the Facebook group chat.
Facebook Help Center thread about Facebook Group Chat has been filled with concerns, questions and complains about altering the Group Chat.
So what's the real answer about this case?
At the Facebook Help Center, under Bugs and Known Issues, here is the answer of Facebook:

The group chat feature isn't appearing for my group.

Group chat has changed. In certain groups, you'll now see the option to message other members of your group. This way, you can contact any group member even if they aren't available to chat.
If you're having an issue with sending group messages, please let us know.

So how to message members on the Group?

How do I message members of a group I'm in?

Messaging members of a group is currently only available in small groups. To message people in a group:
Go to the group
Click the gear menu in the upper right corner
Click Send Message
Use the checkboxes to select who you want to message, or press Select All to message the entire group
Click Start Chat
Note: Anyone in a conversation started in a group can add other people to the conversation, whether those people are in the group or not. Anyone added will also see all previous messages in the conversation.

So what's the reason behind this? Facebook pushed this changes for the user who is offline can receive a message from his/her friends although the user is offline through his Facebook Messenger on his mobile phone.

You can not chat with your group mates unless you add them to your conversation.

Maybe this is the answer to my question few months ago, why Facebook Messenger on mobile phone doesn't have a feature of chatting with group.

But if you really want to return it back, you can sign for a petition and just pray if Facebook will answer your request.