This is the final part of a 3 part article, titled ‘Soft Attacks on Free Speech’ (see here for part II, which has a link to part I). In this part I briefly look at boycotts and conclude that whilst they can sometimes be regarded as contemptible, with false justifications being provided for them, there should not be a law against boycotts.
The aim of a boycott is to change behaviour through economic pressure. An example of this would be the organisation ‘Stop Funding Hate (“SFH”)’, see here for their website,. SFH seek to persuade advertisers to withdraw from the Daily Mail, Daily Express and the Sun, based on the content of those publications. They claim that these publications propagate ‘hate’.
They do not appear to suggest that the articles in question amount to a criminal offence such as inciting racial or religious ‘hatred’, vague and wide as these offences are. Nor, to my knowledge, do they specify whether hate is being expressed, incited or both. Indeed, so far as I am aware, there is no attempt by SFH to define ‘hate’. Without a definition of ‘hate’, SFH is adopting a Humpty Dumpty approach i.e.:
“When I use a word,” Humpty Dumpty said, in rather a scornful tone, “it means just what I choose it to mean—neither more nor less”. 
Whilst the campaign by SFH may be within the proper bounds of free speech, it goes against the teleological justification for free speech referred to in parts 1 & 2 of this article, namely the intellectual engagement with ideas and the attempt to refute or support them with argument and evidence. SFH instead are seeking, either to silence the papers concerned by bankrupting them, or to procure a change in their content through economic pressure.
“When the drive to maximise readership is the sole basis on which companies decide where to advertise, media outlets may be motivated to boost their sales – and online “clicks” – by any means they can.
Advertising in a moral vacuum can thus create a perverse incentive for outlets to publish hate speech, “fake news” and other content with harmful social consequences.”
Therefore, they implicitly admit that these papers are to an extent, catering to the pre-existing views and preferences of their readership. SFH also implicitly admit, that they cannot or are not prepared, to influence this readership to adopt their own values; instead they want to use economics to ensure that no mainstream publication reflects opinions which they despise but are not prepared to challenge intellectually.
It is reasonable to infer that the advertisers in question had simply made a commercial decision to advertise with the aforementioned papers, without any regard to political issues. To say that these advertisers are not obliged to fund the papers is a straw man argument; the point is that SFH are via economic pressure, seeking to silence ideas and not refute them, to stifle such ideas rather than to engage with them.
However, none of the above leads me to conclude that there should be a law to prevent boycotts and/or the campaign by SFH – of course there are many different boycotting campaigns involving very different circumstances. If it is and should be, lawful, for commercial actors to withdraw their business then it there is no justification for creating a law against persuading such actors to exercise this right. Those who object to economic pressure being used to stifle and silence ideas, should organise and seek to punish companies who themselves stifle and silence ideas through their behaviour, whether such companies are pushing an agenda or just virtue signalling due to pressure from the likes of SFH. It could be made clear that any counter-boycott would cease, once the company changes its behaviour.
Whilst ‘hate speech’ laws are a powerful and unjustified attack on free speech, I would opine that the economic pressures against the expression of certain views, are at least as harmful to the aforementioned teleological justification for free speech.
For the reasons provided, I would advocate legislation in the areas of employment and service provision but not against boycotts. Boycotts should be dealt with via counter-boycotts. The proposed legislation would assist with safeguarding free speech but with the number of people employed by the Government, large corporations and the power of such entities, it may be that only fundamental economic reform will allow for true free speech within society.