They are jeopardising the enormous popularity and community goodwill attracted over 30 years for the sake of a dirty tricks campaign.

It's not as if they are still languishing as a minority group on the fringe. Their parliamentary wing wields enormous power in Canberra and Tasmania and is entrenched in political systems across Australia.

Corporate watchdog ASIC is investigating NSW environmental activist Jonathan Moylan after he distributed a fake ANZ Bank statement claiming the bank had pulled its $1.2-billion loan to coal miner Whitehaven Coal, and for impersonating a bank officer. The hoax wiped $314 million from the value of the company, financially hurting many small investors.

The Australian Greens backed his deception. Mr Moylan apologised to affected investors but, like the Greens, has argued that Whitehaven's coal venture was far more harmful than his actions.

Australian Greens leader Christine Milne and her colleague Senator Lee Rhiannon congratulated Mr Moylan. In other words Australia's foremost Greens leader condoned a potentially illegal act. She should take a reality check on her arrogance.

Perhaps she would like to face the mums and dads who lost financially to Mr Moylan's foolish actions and explain how this manipulation of their assets was justified.

If ASIC prosecutes Mr Moylan he faces up to 10 years jail and fines of about $500,000. The penalties are severe because deception and dishonesty in the marketplace has the potential to cost others dearly, whether they be institutional investors or individuals.

To financially harm an investor through dishonest practices is really no better than stealing or vandalism. Does the end justify those sorts of means?

Certainly not. Almost everything the conservation movement has done to produce some historic environmental outcomes over the past 30 years, has been achieved legally. Senator Milne just rewrote the manual.