I think this is supposed to be working; I'm using the same setup as everyone else in my org, and pip is installed in my system environment?

It shouldn't be working. Danny is right. The alooma setup.py:

sr/bin/env python
from distutils.core import setup
try:
      from pip.req import parse_requirements
except ImportError:
      from pip._internal.req import parse_requirements

install_reqs = parse_requirements("requirements.txt", session=False)

reqs = [str(ir.req) for ir in install_reqs]

setup(
    name='alooma',
    version='0.4.15',
    description='Alooma python API',
    author='Alooma',
    author_email='<mailto:support@alooma.io|support@alooma.io>',
    packages=['alooma'],
    install_requires=reqs,
    keywords=['alooma', 'api']
)

The fact that PEX sees pip on you machine and allows it to leek in to the environment while executing this setup.py is unintended and a bug.

Ah, thanks for your reply. That makes sense. Is it possible for me to patch the alooma target and attach the pip dependency?