Mindjet developers should have corrected that.
However it was already removed from the functionality in previous versions MM2018 and MM2017.
Have you skipped some versions?
And just to understand your request better.... What are the benefits of exporting as powerporint Objects?
I can see why you might want to do this, even if the default objects in PowerPoint are fairly ugly, and I don't understand the logic behind dropping this feature.
However, as you've probably discovered, there are a couple of work-arounds. You can export the map as bullet points to PowerPoint, highlight the text then apply the appropriate SmartArt graphic which will convert the text into PowerPoint objects. The problem with this approach is that PowerPoint defaults to making the central topic the slide title, when presumably you want it to be part of the set of objects.
You may be able to control this via a PowerPoint template but I haven't tried this. Another alternative is to export from MindManager to Word then copy the text from the Word document and paste onto a blank PowerPoint slide. You can apply the SmartArt graphic and the text including the central topic will be converted into PowerPoint objects.
I'm hesitant to suggest things already included in the excellent MAP add-in for MindManager, but consideration should be given to negotiating with Olympic Limited to acquire MAP's ability to export images of MM slides as either PowerPoint slides or images in a Word document. This really should be a core feature of MM's export facility, along with the ability to export slide content as PowerPoint Objects.
The facility to export slides as images could be expanded to give users the choice of either medium or high-res image export to either PP or Word, and in the case of PowerPoint the option to select whether the exported MM slide image is titled or covers the whole slide without a title.
In both choices there could be an option to include or not include topic notes as speaker notes, and the "titled" option could also include two other sub-options: leave the title blank, or use the topic text of the parent topic in the slide as the default PP slide title text.