This is improvised slat armor[0]. It is intended as defense against projectiles that use shaped charges[1] which are most effective when detonated at a designed distance from the target. The slat armor is meant to detonate them at a larger than optimal distance.

It is not expected to defend against all weapons, rather it's part of defense in depth. Whether it's effective against shaped charge projectiles will largely depend on the construction and spacing of the slats. To dismiss it outright displays a pretty shocking level of ignorance or agenda on the part of TFA.

Edited to add:

I read T-entire-FA via the archive link up-thread. There is meaningful discussion of slat armor in it. I remain convinced that there's room in the taster portion of the article to suggest that the improvised armor isn't a purely ignorant addition to the tanks. I would further suspect that hinting at substantive analysis below the fold stands to sell more subscriptions to The Economist than what they've included, which is, at best, one-sided.

[0] https://en.m.wikipedia.org/wiki/Slat_armor

[1] https://en.m.wikipedia.org/wiki/Shaped_charge