This is wrong. Permissively licensed (MIT, BSD, WTFPL, Apache, etc.) free software is still free software. Open-source requires the provision of the same right to distribute modified copies as free software does.
Copyleft licenses like the GPL assert the same right recursively for downstream users, more or less (details vary between copyleft licenses). But granting the right (to distribute modified copies) to first-order recipients of the source code is common to all free and open-source licenses. That's great! I imagine it's what you're getting at with the phrase 'properly secured'.
But to qualify as open-source, a license must allow redistribution of modified copies, and copyleft is not the only kind of free software license
See (for instance) the Free Software Foundation Europe's FAQ entry 'what is open-source software?':
Copyleft licenses like the GPL assert the same right recursively for downstream users, more or less (details vary between copyleft licenses). But granting the right (to distribute modified copies) to first-order recipients of the source code is common to all free and open-source licenses. That's great! I imagine it's what you're getting at with the phrase 'properly secured'.
But to qualify as open-source, a license must allow redistribution of modified copies, and copyleft is not the only kind of free software license
See (for instance) the Free Software Foundation Europe's FAQ entry 'what is open-source software?':
https://fsfe.org/freesoftware/legal/faq.en.html#opensource
as well as the Criterion 3 of the Open Source Initiative's open-source definition: https://opensource.org/osd