AVAST "experts" introduced some detection rules which identified all Delphi executables as potentially dangerous.

If you make a small Delphi program without any link to the VCL, with some access to the Internet, a lot of "cheap" AV programs would identify this program as a danger.
This is the symptom of poorly maintained heuristic rules.

AFAIK it is the first time their "rules" have been defined so poorly that even ANY Delphi program is detected as dangerous.
AVAST team should not be proud.
A simple test with a fixed void Delphi application would be enough to detect such regressions.

At least, they reacted promptly.
There are still a lot of Delphi programs in the wild! ;)
They claimed this has been fixed by now.

It certainly did cost a lot of money of IT professionals, using Delphi applications.
But you can ask for your money back, when something is free, right?

In all cases, what is needed is to check any suspicious executable using meta-scanners.
See for instance how a valid Delphi executable was checked today, using VirusTotal online service.