The quote that is from Geshe Lhundub Sopa is from the book titled "Steps on the Path to Enlightenment: A Commentary on Tsongkhapa's Lamrim Chenmo".
In the book it tells the difference between stealing from Buddha, Dharma and Sangha. To steal from the Dharma is like if you steal an image of a Buddha, or take scriptures, or use something intended to be offered to the Buddhas and the 3 Jewels for yourself. Stealing from the Buddha or Dharma, one is able to purify the karma of the action through the application of the powers of confession and regret, subsequently offering something similar to the item you took.
However, stealing from the sangha, which is stealing directly from the monks or nuns, imposes a much heavier karma. One is not able to purify the karma just by replacing the object itself. One will have to experience the karma of the action, and that is being born in some kind of hell. Stealing from the Sangha will provide tremendous obstacles to their Dharma practise and it in turns harms all sentient beings as because the Sangha would now have to worry about their sustenance, which they receive maybe during alms, instead of having full concentration in practising and spreading the Dharma.
Stealing from Sangha, or any pastors, prophets, rabbi, definitely does show that we are in a degenerative age. Why downgrade religion, or take advantage of it, when all it is is to help people? There ahve been many cases of this, not just in the Buddhist faith. Mankind is sometimes ruled by their own greed.