Margaret Walker writes: Re. “Essential: elections, the economy and Australia Day love/hate” (yesterday). The Free Dictionary defines jingoism as “extreme nationalism” characterised especially by a belligerent foreign policy; chauvinistic patriotism.

Characterising people who say they will celebrate Australia Day as “joining in the jingoism” as Bernard Keane did is a poor use of language.

Western Sydney

Niall Clugston writes: Re. “Deconstructing Tony: Abbott and the manufacture of authenticity” (yesterday). When Bernard Keane deconstructs Tony Abbott, he should also try deconstructing the western Sydney of the “politerati”.

Keane talks about Abbott posing as a “knockabout western Sydney bloke”. While Keane points out Abbott is hardly “average” in his education and income, he overlooks the fact that 86% of Lidcombe, where the recent rally was held, had both parents born overseas at the 2011 census. While there is no reason a Chinese or Korean person cannot be a bloke, or be knocked about, Keane’s language conjures up the spirit of a “westie” who has been in decline since the 1970s.

And Lidcombe is not Liberal “heartland”: it is part of the relatively safe Labor seat of Reid, and worlds away from the outer suburban seats that the Liberals currently hold.

John Doyle fan club

Melissa Madsen writes: Re. Media briefs (yesterday). I’m not sure why Crikey has taken such a strong dislike to John Doyle and his stint standing in for Fran Kelly on Radio National’s Breakfast program. His relaxed and whimsical approach to morning radio was a welcome way to ease one’s self back into the working year after the Christmas/New Year break. Much like Clive Robertson used to be on ABC Classic FM in the mornings.

Silence on centre court

David Salter writes: Re. Comments (yesterday). The maths proposed by Gervase Green to show that a batsman would not be disadvantaged if the sound of a Test-standard cricket bouncer hitting the pitch were obscured by the bowler making a sound look convincing — until they are compared with the equivalent figures for tennis.

Even if we accept an initial delivery speed for the bouncer of 160km/h, that’s significantly slower than a top-rate men’s tennis first serve at 210km/h. And, unlike in cricket, the tennis ball doesn’t slow down significantly after bouncing.

Meanwhile, Tristan Edis should know that the ABC is a Corporation. It ceased being a “Commission” in 1983.